I slowly worked a finger into her with one hand, while I softly rubbed and circled her clitoris with my other hand, to help make sure she was as lubricated as possible. It didn't take long before I could get my whole finger in her; when she was a little wetter, I started working a second finger in – again, starting by just entering her, getting my fingers lubricated, and withdrawing again. I alternated that with putting just one finger all the way inside her, so that the one finger was always well-lubricated. Gradually, as she relaxed, I was able to get two fingers into her further and further – until I finally got both fingers all the way inside her. With that done, I slowly withdrew them nearly all the way, and then slid them back in again – getting her used to the size of them. While I was doing all this, I continued to rub and circle her clitoris with the fingers of my other hand – and she used her hands to squeeze her breasts and tweak her nipples. When I was finally able to get both fingers into her fairly easily, I went to the next step: turning them around in her, so that instead of being stretched in just one direction, it would stretch her out all the way. I again went through the process of going a little way, then backing off, then going a little further, then backing off, always going a little further than before. Finally, I was able to move my fingers around in her freely – she was still smaller inside than my penis, but now the difference wasn't so great; and she was starting to enjoy the sensation.
When I slid my fingers out of her for the last time, they came free with a barely-audible 'pop'; she looked down at me as though she was both relieved to be not so filled again, and anxious to go on to the next step.
I moved back up next to her, and told her "Now, while you're recovering from that, and getting ready for the final part, we find something to do to keep ourselves occupied". She smiled at me, said "I think I know what we can do", moved herself down so that her face was in my crotch, and swung her leg over my head, putting us in '69' position. I told her "whenever you feel like you're ready, we can go on to the next step. If you change you mind, we just continue like this". She mumbled her agreement and understanding from around my erect penis, and I started kissing the insides of her thighs while softly stroking her from her clitoris to her anus.
For her part, she started licking me – the insides of my thighs, my balls, and my penis. As I changed from simply kissing her thighs and pubis to licking them, and 'biting' them with my lips, she started repeating my actions – mouthing my erect penis and testicles, nibbling the insides of my thighs. I 'upped the ante' when I started taking her vaginal lips in my mouth, and softly 'chewing' on them, and gently sucking on her clitoris. She responded by taking each of my balls into her mouth and rolling them around with her tongue, and gently sucking on my penis – not just the head of it, but from the side and bottom and any other way she could get part of it in her mouth.
After several minutes of this, she was pressing her clitoris against my tongue; and her juices were flowing out of her in a steady stream. Her vaginal lips were fully extended, and separated, clearly exposing the entrance to her vagina. Finally, she released my erection from her mouth, and said "Oh,*god*. I think- I KNOW I'm ready…". With that, I stopped what I was doing, and helped her get her leg back over my head without hurting me. She turned around, and swung her leg over me, so that she was straddling my hips. She reached down, and started caressing my penis with one hand, and rubbing her clitoris and the outside of her vagina with the other. She looked at me with what can only be described as unbridled lust, and asked "What now?".
I told her that if my penis were wet and slippery, whether from her saliva or vaginal lubrication, it would make things a lot easier. She promptly lowered herself, so that my erection was pressed against the outside of her vagina, and started sliding herself back and forth on it, both spreading her wetness around on me, and stimulating herself even more. As she was doing that, I put my hands on her breasts, and started kneading them, and pulling on her nipples. Then I told her that in just a little bit, when my penis was completely lubricated, she should raise herself up, grasp my penis, and position it so that she could simply 'sit' on it. She nodded her understanding, raised herself up, allowing my penis to rise up from my body, and pivoted her hips so that now the top of my penis was pressing against her vaginal lips, getting my erection thoroughly soaked in her secretions. A bit later, she raised herself up yet again, and when my penis came back up toward my belly, she took hold of it, moved herself forward a bit, and lowered herself so that I was slightly penetrating her. She paused for a bit, which I was grateful for – I needed the time to get control of myself, and not blow my load too early.
When she had gotten herself ready again, she started lowering herself some more. At first, she had trouble making any progress, until I told her "Relax. Take your time. I'm here, and there's no hurry". That seemed to help her, because I could feel the entrance to her vagina relax some; when she started lowering herself again, I could feel that she had relaxed enough that my penis was started to slide into her – though slowly. She kept lowering herself, allowing my erection to press harder and harder against the entrance to her vagina, until finally, with a slight 'pop', the head of it slid inside the entrance to her vagina. She gave a little yelp, and stopped; I had to reassure her that I wasn't going to do anything to hurt her, and that we would go only as fast as she wanted. Then I told her to just wait a bit, and let herself get used to the feeling and relax, before she tried to go any farther. She bit her lip, nodded, and held herself still.
While she was getting herself ready to continue, I did my part by caressing her, squeezing her breasts, softly pulling on her nipples, and even rubbing her clitoris in little circles – I could see it peeking out at me from where her vagina was wrapped around the end of my penis. After a minute or so, she had composed herself, began lowering herself farther onto my penis. When she'd gotten another inch of it inside, she stopped; and I suggested to her that she raise herself up a little, to make sure that her wetness kept us both properly lubricated – reminding her of how I had put my finger inside her. She nodded again, raised herself up a little, letting my penis slid out of her about half an inch, and then lowered herself some more – this time an additional half inch, or so. She paused for several seconds – again, giving me some time to get more control of myself – raised herself a bit, and lowered herself another inch or so before I could feel the head of my penis hitting the obstruction of her hymen. She gave a little gasp, and I told her "That's your hymen – your 'cherry'. You've got a couple of choices, now – you can go ahead and 'push' yourself past it at one time; or you can use the progress you've made so far, and let my penis bump into it each time you come back down, and simply wear it out. Pushing now will make it hurt more but have me all the way inside you sooner; wearing it out will hurt less, but take longer. We've got plenty of time, so you can do whichever one you want – I'll be right here". She smiled at that last bit, and I could feel her starting to relax more, though every time she moved – or even breathed – I could feel her vagina tighten around my erection. The stimulation from that was enough to keep me hard, and the lack of real movement gave me a good chance to keep control of myself and not fill her young snatch with my cum. I needed the control, because her vagina was incredibly tight (even with the loosening I'd given it with my fingers), hot, and wet. It was even better than my own first sexual experience!