Can a girl lose interest because she is scared? Girls I want your opinion!?

So I went out with a senior and I'm a junior. This was the first relationship for both of us. She was not the type that opened up for fear of being hurt or hurting others. But I told her how I felt about her and from everything started. We held hands, kissed, hugged, laughed. But my parents didn't let me take it to the next level and make her my gf even though I tried hard to convince them. I told her and she decided to keep the relationship the way it was. After that she grew quiet but we were still affectionate. However a week later she said that she thought it was better if we were friends becuz there was a lot going on with her and felt it wasn't fair for me. She said she still liked me but that I should date other girls. After that I was hurt and didn't talk to her but she told she didn't want me to ignore her and that we should still talk. She is going to prom with this friend of hers and they call each other hubby and wifey. She said they are just good friends though. Why did she suddenly end it? Was she scared of liking me too much or did she like someone else? Was it because of college? I need am outsiders view on this. She seems happy but I still miss her even though I moved on...