Okay, how do I put this. Is it weird that I'm a girl and might like a transgender boy? I think it's okay, because they wanted to become a boy, and so now they are. Opinions?

I don't think it's weird. If you find someone you're attracted to and makes you smile lots, it's all good.

You can't help who you like

No, because he is essentially a boy.

How old are you?  I think you might be too young to be interested in a relationship at this point.  When you're ready for this .. You'll know what's right for you to do.

Well, since you are a girl, being attracted to someone who is a boy is certainly a typical situation.

But a transgender male is "a person who was assigned female at birth but whose gender identity is a man." (internet)

My only comment is that if a girl being interested in a boy is a relatively safe, predictable shallow pool,  then be aware that there may be some very deep holes in your pool and you may have to be able to swim to survive in those waters.