Should i ask her out?

I know this girl X for the past five years. I initially met her on social networking and we went on to become good friends online and offline. But my conversations with this girl initially was only through chat or texting on the phone with the occasional phone call.Mistake 1: I did have a crush on her initially but because a couple of her close friends told me that it would be virtually impossible to ask her out since a lot of guys had already tried. So i took it easy since i enjoyed our friendship and did not want to lose her. This is when i started going out with another girl Y. A few months into our relationship i found out from a mutual friend that X had a crush on me too and she wanted to go out with me. Before i could tell her anything she found out about our relationship and I admitted to it. The thing is she did not know that I knew she had a crush on me. she just backed off. she then started going out with one of her friends. We went on with our respective relationships for a couple of years and then I started having problems with my girl. This girl helped me out with a few tips and things were going ok. Down the road she too started having problems with her boyfriend and I offered some piece of advice myself. I then had to leave my country for my higher studies. About a year back I broke up with my girl friend and I was kind of heartbroken.To give you a gist of my relationship with Y. It was pretty ok in the beggining but then I began to think that it was not love and just infatuation. So i got over it pretty easy once we broke up. Surprisingly X broke up with her boyfriend at exactly the same point of time. Mistake 2: I Found this pretty strange and spoke to my sister about this and I wanted to ask X out but to me it seemed like it was too soon after my previous one and hers too and it wouldve seemed like i was seeking refuge. But the fact remains that i think of this girl a lot. I enjoy talking to her and she makes me smile every time i talk to her. But for the past few months shez been busy with her university work and our conversations are too short these days. I had visited my country for new years and for some reason or the other we could not catch up with each other. I intended to atleast tell her i had a huge crush on her if not asking her out. Now i am back outside my country. What do you think her reaction would be if i ask her out? Do you think she will still be interested in me after so long? Please advice on this! I cant stop thinking of her