Ewww!...
I know guys like that and honestly, the lie "But she said she was 25!!" doesn't cut it for me.
She's 15! It doesn't matter if she tries to act/look older, she is still 15 and I bet other women could see she was 15. Problem with guys though is that they deny it, they just see a girl that's easy, nothing else.
I know guys like that, I've had crushes on them, and no of them ever changed...
Go find a guy that will apperciate a woman, not a girl