Songs about having a teenage crush?

I like dedicating songs to people, and I'd like to dedicate a secret
song to the person I like. I couldn't think of any song that can
relate to my situation, because I can't date the person, but we talk
and we're acquaintances. Do you know any songs about this? I'm sure
you've all had crushes that you can't do anything about at some point
in your life.

Please, no mainstream, hip-hop, or country music. Alternative rock is
the best song genre for me, but I'm open to anything else.
Jaison- the song's called 21 Guns. It's a good song.
I said no mainstream, but thanks anyway.