Does she flirt with me or what the meaning of this kind of girl behavior?

I know this girl for one year now. I have asked her out two month ago and she said “no”, so I back off from her. I didn’t talk with her any more from that point. but today she saw me and I wanted to go without she notice me and she stopped me and asked in a nervous why I’m ignoring her, why I don’t say “hello” and it look like she is angry with me. It’s strange, I just thought she don’t won’t anything to do with me and I don’t wont to be in her “friend zone” so I let it go.

Now I have a new girlfriend and this thing really bothers me. What should I do? I like them both, but I can’t understand the meaning of that girl talking to me in a rude way while I just want to go on with my life and forget about her.