Yup, so today this guy at school asked me out. I'm out to a few of my friends at school but no everyone. He doesn't know.

The thing is I really like him, but I don't want to be someone's girlfriend and I don't really want to tell him I'm trans.

Anyone able to offer incite?

Would you be comfortable with saying that you're questioning?
If not, you could say you aren't ready for a relationship atm.

Just a suggestion..
Try being friends first, take your time.
Hang out with him around your friends who use your male name and male pronouns and see how he reacts.