I got this girl's number over the weekend. I met her a few times before over the summer, she is best friends with my friend's girlfriend. We've been flirty with each other at bars and even danced with each other once, but nothing other than that. I ran into her this weekend and she seemed very flirty and when we were going from one bar to another, she was very concerned about whether I was coming along and kept asking me if I was and seemed happy when I said I was. At this other bar, she was very flirty and even mentioned how we danced once at this bar. As we parted ways she said that she hopes to see me next time, I said, well can I just get your number, she seemed excited about it and gave it to me without hesitation. Two days later, I even see a friend request from her on Facebook, meaning she must have been thinking about me and decided to search for me on Facebook. So, do you think she is interested and that I should give her a call and ask her for a drink? I've always been the guy who never picks up on a girl's signals of interest, I always just assume they are being super friendly because I am friendly as well. Should I go for it?

Well judging from what you wrote above, I would assume that she does like you.
But as with anything in life you won't know till you try it.
I think you seem to be sort of overanalyzing the situation. Whether it's a pure friendship interest or a relationship interest she's showing, she is in fact showing some sort of interest. You might as well go for it. At least its not a hopeless situation. Ask her out for some one on one date and take it from there because you guys seem to be hanging out in groups or with other friends. If she says yes, than she does probably like you, and than can you can base your decisions/ choices from there.

Yeah, I tend to overanalyze everything

No need to think, because she's the one with the answer. So nor matter how much you analyze in your own mind, her answer isn't going to change.

Just ask and see what she says.

Well, for someone "who never picks up on a girl's signals", you sure did get the vibe from her didn't you?

Never question if, question when.

She's probably wondering what's taking you so long.

Good luck to you.

Its worth taking a chance, and finding out. Call her. I would.

Why don't you ask her if she's interested. If she is, ask her out. Don't read too far into the situation. Every woman is different, so don't try to read their "signals," to see if they're interested. Instead, be honest and ask them straight up.

It doesn't take much- most women will give awkward looks to guys who ask them out by "beating around the bush," instead of getting straight to the point.
If you want to get to know the girl better, bar scenes, and drinks may not be the most fool-proof plan for a date. Why don't you do dinner and a movie? Coffee, or soda? Make it a point that you want to get to know her better, and make it special, as oppose to something you would do with a couple of guy friends every weekend.