Why did she act into me when we were alone, but got uncomfortable when her friends were around?

I went on a first date with a girl which I thought went well. She invited me to a theater performance she was in the next day. I went, but after the show she started acting awkward, distant and really nervous talking to me. Oddly when I talked to her other friends who came, they really seemed to like me. One of her friends invited me to their party after and so I went. She seemed unsure about it, but then decided to ride in my car to go there and relaxed when she got alone with me and started joking around. But at the party she got awkward and nervous interacting with me. So I didn't really talk to her much. When I left she didn't even seem to want to hug me and looked really stressed out. There was no other guy she seemed interested in. Her friends asked me to hang out again the next day but I turned them down. It also seemed like she hadn't told anyone she went out with me. If she doesn't really like me thats fine, just confused by what was going on.

Why did she act into me when we were alone, but got uncomfortable when her friends were around?
Post Opinion