Am I her friend or is she interested romantically?

So my sister introduced me to a girl. Who I like, and for the most part I also think she likes me. We started to talking to each other about common interests (music, movies, hobbies), then in class we became closer. We both always seem to have a great time alone, doodling and flirting mildly. Then there was a party where we got kinda of tipsy, shared a couple of beers and started going around calling ourselves King or Queen. When people asked if we were a couple we just responded “We are King and Queen!”. She always stayed close to me during the party. She is comfortable around me. The next day we had a movie night together with some friends and then I started sensing some distance. Or at least I felt distant. I later got to know that she might just be thinking me as a friend.

So pardon me for being a bit… well “Does she like me, or does she not” but my question is what signs should I look out for to firmly distinguish if she views me as a friend or a potential boyfriend. And if she does like me, when to make the right move?

I asked both my guy and girl friends and the guys said “Do it”, and the girls said “Wait”.

What to do?