Obligatory notice that this is a throwaway.

So I (18f) was asked out by my friend (20f) a few days ago. I'm openly bisexual so her gender is not the problem. She approached me when our whole friend group was hanging out and told me that she "really liked me" and then waited for a response. I had kind of suspected this was going to happen for a few days, but I wasn't sure and hadn't prepared a response, so I just went "sorry, I prefer us as friends" essentially, but with all the grace of someone putting their foot in their mouth. She took it gracefully, and before I left came up to me to make sure I was still okay hanging out with her, which I am. 

HOWEVER, the past few days since she has asked me out, she has been pushing our friendship in a more touchy-feely direction than it had been before. To clarify, that means things like asking for hugs, sitting very close to me at every opportunity (thighs touching). Now, I am a fairly physically affectionate person and have that kind of friendship with some other people in our friend-group, but since she's only doing this after she told me she liked me, I'm kind of uncomfortable. 

Some other things that might be important to note:

1. This friend-group also contains my ex boyfriend, and we have managed to regain our friendship and be okay around each other, even though we are nowhere near as close as we used to be
2. The girl who asked me out is someone who I had planned to live with, along with two other girls, in an apartment-style dorm next year, and we are currently filling out our housing applications for next year.
3. Even though the rest of our friends might have overheard our various conversations I don't have any idea if they actually did and I have not asked them their opinions on the situation.

So, I'm feeling very strange right now and turn to you to tell me if I'm being an asshole to my friend.