I really like this girl. We are best friends and I've liked her since the 3rd grade. But if she rejects me, it would seem weird. So what do I do?

You're both too young to date. It could be that her parents don't allow her to date, which means she's not allowed to. It could also be that she only likes you as a friend. That's the more likely reason.

So be her friend. You can't force someone to like you the way you like them.

Ever since I was in 6th grade back in the 70's I always thought it sounded funny 'going out' meaning walking the girl to her next class. Right now you are having an interest in getting to know someone of the opposite sex, rarely does that make it past a couple months to a year. Very few say they married their childhood sweetheart. So the closer you can keep it at good friends and not get head over heels, at least in your younger years' the better it will be. A lot of times at your age 'going out' usually ends up in a drifting away sort of 'break up'.

Please define what you mean by asking out. Knowing what you mean can help us answer you. Also knowing your ages can help.

Her age would be about 11 in 6th grade.