I like my best friends sister

Me (15) my friends sister (14)

So he’s one of my best friends, and recently he came over with his sister cuz my mom invited them. They stayed for a bit and she was chill. Then a few days later they came over on the weekend, and my friend mostly played on the computer and me and her talked a lot. At first she wasn’t comfortable to even go to the bathroom without asking and at the end she was comfortable enough with me to not let me choose what show we were gonna watch lmao. Any way she even talked about her instagram, and said she won’t give it to me cuz it’s “too embarrassing” but then she gave it anyway. Also when all 3 of us were watching a movie we were squished on my small couch, and when my friend and her sister (the girl I like) were touching shoulders she said “move over dont touch me” and we were fully pressing shoulders to feet against each other and she didn’t mind that. We also got wayy more friendly at the end to where we would pull each other around n stuff. Do you think any of this means anything? What do you think I should do?

TL:DR

I like my best friends sister and she was shy asf at first but got super friendly with me later

(Just read the whole thing way easier to understand)