Falling for best girl mate (different cultures)

Hi i am a 23 year old white lad and am falling for my 20 year old Muslim female friend. I have always thought she was really pretty and we have been friendly for around nine months. We had a brief period that through other people causing problems we were at a bit of a distance. Now though we are so close and are talking on the phone until 3/4am the last few nights. She's a very private person and also has a long term partner. She doesn't give her number out easily and it took me a while to gain her trust. While i find her attractive i don't really view her so much in a sexual way, i see her as more cute than someone I'd want to sleep with. It's more of an emotional issue i have with her. Our uni situation is complicated in that she might not get through to next year whereas I'm already through. Some of my mates tell me she uses me for work etc but i really trust my own judgement and she's continually telling me not to do things and to concentrate on myself. I accept she might say that knowing il do whatever she wants anyway though but I'm not at all naive. I think she knows she's got a good thing with me but I'm sure she's no user. This brings me onto the other issue that is slightly more complex. I know people misinterpret anything like this completely and pass it off as a sexual thing. This girl can be quite domineering but is very subtle about it. It's not blatant but little things like it just wouldn't be acceptable for me to call her if she was busy but if I'm busy I'm expected to drop whatever I'm doing for her. She doesn't work while off uni whereas i do and have quite a hectic schedule some weeks. For example if i have a 6am start she's happy to keep me on the phone until 3am then ask me why I'm quiet the next day when I'm simply exhausted. My friends think it's ridiculous and I'm blatantly been used but she's there for me at times no one else is and we have a real connection. I do like her dominating me i must admit, i like the emotional control and having someone to make decisions for me. Obviously this isn't something i can tell my mates but I'm happy this way and sometimes i feel like i need to open up to her but I'm not too sure what to say. I know it's the control thing because I have a lot to do with several of the girls at uni but they aren't like that, they are way too nice and I can't stand that. I don't think i like been treated badly but i don't want to be able to do as i please either. I had a female best friend i was crazy about who took control all the time and as that was when I was at my happiest i don't know if maybe I'm looking for that again. I did post this somewhere before and people even said it can be your relationship with women in general, work, mum etc. My mum was very strict but i also had a very happy childhood and i don't really get what it is i want out of this girl. Do you think i should open up to her or just see what happens.