I need help figuring out what I should do with a situation with a friend I like

Alright, I don't post much on here, I usually have no problem with women except for one thing, I have never actually fallen in love with someone. I am 27 years old and a new Miami, FL transplant for school and career opportunities. I do wear a hearing aid, but that really doesn't seem to be a problem for me when it comes to women or anyone for the matter. I wouldn't say I'm the "hunk"(being realistic) but I feel like I am attractive enough for the girls I want. Ok here it goes, I have been in Miami since January and I came here for the sole purpose of landing a songwriting/production career with a studio or production company. The first few months I was not really meeting a lot of people(due to lack of a car and where I am located in Miami which is right next to two shitty ghettos). So May comes around, and I meet this girl we start chatting, got her number, etc, etc. We finally decide to go out on a "date" and it seemed to work really well, we have aligning interests, and we both admire things about each other when it comes to music and personal things. So we were hanging out once a week(she is a busybody between work and school which is fine) and so I wasn't really looking for anything more than friendship(mistake number one, I'm sure) but as we kept hanging out I grew fond of her. I went to the store down the street from me, and the guy that works there told me that she was into me, and I had the feeling I just never really thought about it. She has a father in the music industry and offered me a huge opportunity so I tried to stay reserved to be professional about it. So eventually I decided to man up and just let her know how I started to feel for her and she didn't know what to say because she said she had feelings for someone else(the worst part is I was getting overlooked for a another girl, not a guy) So, I backed off a little reassessed the situation and decided, well I am a likable guy, and her friends like me, even her closest friend from Mexico who came to visit. So things were kind of back and forth, she would seem interested, through things like really telling me about personal things that you don't really just tell anyone and through certain body language, the inside giggle when I tell a joke, I catch her staring at me alone and with friends, and we do this thing I don't really know what it is haha but like we'll catch each other's eyes and we just laugh at each other. She playfully teases me with the subtle name calling and playful bickering about nothing and then we just laugh about it. So I decided after all of this, to step it up a little, telling her to her face wasn't working, so I wrote her a letter that was pretty sincere on my part and she read it and she told me she cried while reading it. That could be good or bad I know. I just need to figure out how to go about this, should I back off completely, or should I keep trying to pursue? And if I do pursue, how would I go about it? This girl is a real catch for me, for my friends and family and even a couple of her friends I have talked to they all have said we make sense together. Any kind of direction or advice would be much appreciated. Thanks guys and with your help I will keep you all updated on progress.

You told her you were interested. She said she was interested in another person. You wrote her a letter and she said it made her cry (nothing further I guess?). Its her turn now. I suggest you back off. Keep her at a distance. Keep her at a friend level. Don't continue the flirting. If she asks why you are distant just tell her that you can not play the in-between person. You can be her friend or you can be her boy friend but you cant continue being the guy with no role with her. She needs to make a decision.