Too big of an age difference. I was 16 I dated a 22 year old. It didn't work out.
At 16 you have a high school mentality. At 25, high school probably seems like it was ages ago.
If the infatuation is there, it might be fun and exciting at first. But in the end she is still a teenager and unless there is something wrong with her, she will still worry about what to wear to school, the cute boy in her English class, and who will ask her out to the homecoming dance (unless she doesn't mind taking a 25 year old to her high school dance).
Young girls are naive and don't know what they're doing. I wouldn't recommend it, but if you're just looking to have some fun then go for it. Just don't expect anything long term or serious. Good luck.
