Does this girl like me? Friend is setting us up on a double date?

[Charles]

So my friend is trying to get me and this other girl together. My friend has a girlfriend that is friends/roommates with this other girl. My friend said he's been talking about me to her for a while now and he thinks she likes me. Anyways I met her the other day and she asked me if I was friends with this kid... who is my friend that wants me to go on the double date. When we talked it was just the two of us. Anyways I added her on facebook and she's followed me on twitter and instagram.

I just feel weird because I don't even have her number and I almost never see her around campus at my college.

When should I ask for her number and do you think she actually likes me? She just added me on twitter, so she must have been thinking about me.