There’s this girl in my class who I’m absolutely crazy about. I want to ask her out, but we never talk, and I guess you could say she’s out of my league. I keep thinking that there’s no way she would ever say yes and that there are more fish in the sea, but I’ve never felt the same about anyone, and I haven’t met anyone like her in my life. I always fear rejection, and I don’t want to let it go, because she seems like the only person for me. Could anyone advise me on what to do?
LemonVibe 
Ask her out. All she can do is say no.
Yes, you should just ask her out, but the bigger problem is that you’ve built her up in your mind to be “the only one for me”. You’ve created a situation where if she rejects you, you’ll feel as though you’ve lost everything, that you’ll be alone forever.
To be honest, you’ve created an image of her in your mind that is unfair to her. Even if she said “yes” there’s no way another human being can live up to such an idealized image. We’re all flawed, we all occasionally disappoint the ones we care about. Making her “the only one for me” is an awful, awful burden to place on someone.
I know how you feel 100% and let me let you in on a little secret that boys are usually totally oblivious to:
Girls don’t like to let on that they like a boy, because they want the boy to be the one who starts up a conversation.
Depending on her, this girl may like you, or may not like you. Don’t start by asking her out. Start by getting to know her, invite her to sit by you at lunch, asking her about school or family, ask her about something she likes and try to find common interests. You can try to bond over these interests. Keep it suttle, but not to suttle! If a girl believes you aren’t interested, they’ll lose interest. Eventually, ask her out! Be confident too, because you want the girl to feel condfident about you, and if your not, it can feel awkward and the girl may feel pressured. Just remember if you dont at least tey, you’ll never know if she would’ve said yes! Good luck!