Why would she react like this?

So, I saw a friend of mine a couple of days ago. In her home town. I was with another friend too. She texted me to say that she bunked off work to meet me. Went for coffee. She said she needed to go back to hers after coffee to get her bag. We was on the tube and I noticed she was looking around, our gaze met she quickly glanced away. This happened a couple of times. We ended up at a comedy night, a few times throughout the gig we were looking at each other. This was the third time I had met her. She had messaged me saying that she had bunked off work to meet us.

A couple of days later she had messaged my best friend, (I had asked to meet her once at the end of the month later on down the line) she had messaged my best friend saying that I was being 'difficult' that I kept asking to meet her and that I don't need to come up all the way just to see her. We both felt it was cause I had another friend who was a girl with me , whom she didn't know , maybe she felt jealous or something that I was with someone

Are you trying to date her? If so, bringing a third wheel along isn't the way to go. Ask her out on a real one-on-one date.

We ended up at a comedy night, a few times throughout the gig we were looking at each other. I had another friend who was a girl with me

Nahhh, I wasn't but I am kinda interested in her . This is the third time, I've met her, previous times have been one on one