I can't get in her head

Five years ago I got to know this girl through the internet, I got madly in love with her even though I've never met her before. The problem was she lived very far away but we got together this one time five years ago. I was young and inexperienced at the time and she was my first encounter I had with girls. Needless to say I bombed and after that we never really spoke with each other again. All communication stopped from both parts.

Three months ago I found out she had moved to study in a small city about an hour from where I live and old feelings started to stir up again. By now I have had some experience with girls and wasn't as inexperienced as I was five years ago so I decided to give it another shot. I contacted her and she agreed to meet me though we didn't set a date at that time. After that I started to send her text messages and call her from time to time to see what she has been up to just so we'd keep in touch. Now last week we agreed to get together and watch a movie in the big city where she had to take a 1h 40m bus ride. Afterwards we grabbed a bite to eat. We talked for hours and it wasn't akward at all even though we met only once five years ago. The 'date' went better than expected and I felt that we had great chemistry together. It all went perfect until she slipped in in our conversation that she has a boyfriend. I was shocked because when we talked on the phone she didn't mention anything. Even though it wasn't really a date but more like a long-time-no-see thingy I felt that she should have said something.

Now I believe that for you to give me advice you have to know what this girl is like, and the impressions I've gotten from over the years and the encounter we had is that she is a bit insecure and somewhat a shy person fundamentally. As a guy you'd have to do all the work, she never took the initiativ to call or text me once, and I think that it's just the way she is. Overall she seems like a very nice person and doesn't seem like someone who would trick you or something like that, a very sincere person.

Now back to the story. We talked until the restaurant closed and then instead of her taking the bus home I drove her. I've realized that even after all those years my feelings I had for her hadn't changed that much. Even though she has a boyfriend I feel like I have to pursue my feelings or until she tells me to stop.

Now that's the part I can't wrap my head around. She hasn't told me to stop. She agreed to go to a movie with me even though she had to take a 1h 40m bus ride. She told me that she wanted to see me again. Why?

The other day I even called her and we talked for over two hours. I'm really confused about what's going on right now. I can't seem to get in her head. She tells me she has a boyfriend but she hasn't shown any signs of wanting me to back off. Also I don't know if she likes me that way, the only really sign I've got is that she's been receptive to my approaches.

So I turn to you girls hoping you have a better understanding of the situation than I have. What is she thinking?

P.S. English is not my first language so sorry if there's some things you don't understand.

"She told me that she wanted to see me again. Why?"
"She tells me she has a boyfriend but she hasn't shown any signs of wanting me to back off. "

Who knows? . . .maybe she just wants to be friend or maybe she's in some sort of transitional boyfriend period? . . . but the time spent in travelling is a bit much

Maybe she's looking to cheat on her boyfriend, maybe she just wants to be friends. You won't know until you make a move.

But...

Pursuing a relationship with a girl who is already in one with someone else is never really a good idea. She might have feelings for you and want to be with you, but if your relationship starts with cheating, can you really trust her not to do the same to you? And do you really want to be the guy that interferes with an existing relationship?