I was raised by an older couple so I tend to act a little more mature than some people my age and lately I've noticed that I only attract men in their 20's for some reason. What do they think they see in me that guys my age don't see?
I had an exchange sister who was 15 and straight up looked 25. Couple her VERY womanly figure with the need of validation of an insecure 15 year old and she got a LOT of attention from the guys. Didn't matter their age. She looked 25. Guys in that age range took an interest in her.
They are more bold. You also may be more physically mature. Usually guys go after younger women because they aren't confident enough in themselves or their abilities to go after women their own age. There are some who are simply attracted to younger women.
I would hate to say it, but you're kinda stuck in the in-between. The guys in your age group are ignorant and only care about looks, nudes, and "scoring", and the 20 year olds look at younger girls for either 2 reasons... 1.) they can not date people within their age group and as a result they look to younger girls for hope in a relationship, or 2.) they want to use you for sex... because they think you'll be easy to "conquer". Just face it, generally guys are assholes...
Be careful with that. Some guys who are let's say 3+ years older than you are looking for a younger girl who they can easily manipulate and dominate. Someone to take advantage of. That being said if you're in your teens, a lot of guys your age are just looking for sex or otherwise have much different views. Guys in their 20s are also pretty immature but they do have a slightly more mature perspective... Sometimes.