Can't tell if my friend like likes me

I've know this person since grade 8 and we've been friends. However since grade 11 we've gotten closer and even know she gives signs that she likes me for more than a friend but I can't tell if she's just being friendly. That's sort of her personality (nice, flirty, outgoing) but she does it more towards me than anyone else. Signs are: the odd Text/ phone call late at night, touchy, (hits, makes little fun of me, pinches), jumps on back randomly for piggy backs. Basically she gives signs that with any other girl would mean that she likes me but I can't tell with her. My friends see it too and still don't know. She has had a few boyfriends since we've met but even when she was with them we would go on late night drives, random hangouts and the same old.

Another point to add is that she gets sort of (I wouldn't say jealous) but weird when I talk to other girls. As a test I've flirted with waitress' and she gets sort of mad ("stop flirting with her") and whoever I post a picture on insta or snap of something that might involve me on a date she replies right away and asks who I'm with. That could come after a couple weeks of not talking so it's out of the blue.

I should add that I'm sort of shy and a tad insecure in the sense that I can't see her liking me for more than a friend which might be part of the reason why I'm asking this now.

I want to make a move and tell her I like her but I don't want to be wrong and lose her entirely. She is out of my league and could get any guy which is also why I think she's just being friendly

Thoughts?