Why do younger girls like me and not girls my own age?

I'm in 12th grade and all the 9th grade girls are all over me, they always talk about me and whisper when I walk by, and say I'm the most handsome in the school. I',m flattered and all but they're all to young, and why don't girls my age feel like that about me? I'm around 5'6 and some say I have a younger face but I still look my own age and I want someone my age to feel like the way they do.