I'm 21 y/o guy. I like a girl that is 2 years older than me, and that is the sister of my friend. We sometimes hangout together but always in a group(I never saw her at my friend's house - we've been friends recently). One good thing is that she knows I exist lol, and she is "closer" to me than my friends/her new friends in the group.

Now I know that this situation is kind of specific, but in general how to deal with girls older than us to make them feel that we are interested? and how to deal with the sisters of friends?

And in my situation: how to deal with the sister of my friend that is 2 years older than me?

Thanks guys