I really like this girl I know but is it OK for a 12 year old boy to date or like a 13 year old girl and also I'm afraid how to tell her how I feel because I'm scared I will be turned down and I'm about a inch taller than her

Do your parents allow you to date? Do hers? This needs to be determined first.

What can dating mean at your age. You don't have money to take her "out".

Frankly, I think you are trying to grow up too fast.

Im afraid that this girl I like will turn me down a for some reason I cry myself to sleep

Sure, she might turn you down. You are both young and she might not even want a boyfriend.
BUT let's talk about what it means to 'turn you down.' That requires a direct question, a concrete request to go on a date or something. Why jump into the deep end of the pool? Talk and be friendly. The easiest way to be liked is to show genuine interest in someone, to ask about their life and family and likes and dislikes, not shot out like pepper spray all at once, but here and there, and a few casual compliments thrown in. Don't try to be clever or flip or amusing or know it all or anything - concentrate all on her, not yourself.
THAT'S how you get someone to like you. And if her heart doesn't go pitter pat but she still does like you, so be it. No harm, no foul. She might go for you though!
If you still are crying after a failed attempt, then come back here and we all will try again.

I've merged your threads, if you have any follow-up please post it to this thread.

You are much too young to be getting so emotional over a girl. You are a victim of the media hype about dating and relationships. You are still a child, enjoy being a child.

Thanks I think your right I'm to young

I understand I'm to young

How about just being friends, hang out, do things at school and in groups together