well first of all, you cant just tell her like that that you love her, ask her on a date, take her to walk, to movies, make her company, flirt with her, walk with her after school, and then on a date, after some dates tell her how you feel, dont scare out!!

It doesn't have to be a big thing.
I find the easiest way to tell someone what I really think is to keep it casual. Maybe even in a light-hearted, almost "joking" manner, but let your eyes signal that you're serious.
Also, just be sure it's actually love before you jump in to anything.
Emotions are tricky, and this could just be nothing but infatuation at the moment, which usually passes.
You might want to give it time first, but if not, then like I said. Just let her know in an easy, simple way.

Well, if you feel that this girl is "the one" (not a crush) then I say go for it! But first make sure your alone with her, (that way you won't get nervous and interrupted by other people) look into her eyes and confess to her your true feelings, the worst thing that could happen is that you get rejected, but if she does rejects you then...maybe this girl wasn't "the one", just have confidence, think positive and everything shall go well, Good luck and take care always~