shh.. an easy question! Ok.. sorry, not belittling your plight... just letting you know that it does get easier in life in some aspects (& harder in others... )
Anyways, first...be happy. Just be happy about life in general. Let Girl #1 tell your crush you love her. If your crush asks you in class, let's say you're sitting down, you turn to her & you look at her dead in the eye like it isn't a big deal AT ALL! and you say verbatim: "yes, it's true." and you just turn around & you go about your business. As a girl I am telling you... I may make you my boyfriend then & there (if I am mature) OR...I may tease you and tell all my girlfriends (which means I am immature & you don't want me anyways!!!! trust that.)
Just keep being cool, confident (not overly...please), and be honest. This whole system we have created in society in which we can't be honest about our feelings SUCKS!
& leave Girl #1 alone.. she deserves none of your energy or time.
Be happy & good luck