Hi Wohochi,
4 years has past since you last knew each other – how do you know you are compatible at this time in life? You’ve had a few conversations with her, but she may have changed and so may have you, are you compatible?
Also, do you like the fact that she has a boyfriend and is talking or thinking about you in any way? What if you get together and another man comes along who she takes a liking too (I know the circumstance is different because you were together once)?
Just my opinion, but something to think about