I had a few girlfriends this hot between ages 16 and 25 or so. Still doing well but this level of youthful perfection doesn't really exist past college age.
OP, here's my advice to you: take all the photos and videos you can. If she wants to be a slut, enable it. She wants to eat pussy? Find it and film them. She wants to get gangbanged? Find the right guys and turn her out. Clearly you have a nice dick and she loves it. I know the feeling. You own her right now. Turn her the fuck out.
When these youthful moments end, you'll still be fapping to everything you did.
Here's a girlfriend I had at 21. She was 18. She's not particularly hot anymore and it's beside the point... we don't talk. She worshipped my cock but still wanted to fuck three guys with me filming her and we never made it happen. I know she would have actually done it because her first boyfriend did MFM with her and she was obsessed.
You know what I wish I had right now? Those tits bouncing between two hard cocks.