Very cool! I wasn't aware that the string libraries in FL Studio could produce that kind of sound (haven't really used the program, to be honest). You've definitely absorbed a lot of musical know-how from your years as a musician, even if it's not all, as you said, things you can put into words like music theory. As far as constructive criticism goes, there were a few places where a dissonant note or two jumped out at me, but nothing too noticeable. The overall mixing is pretty good as well -- the parts all come out when they need to and fade back into the texture appropriately. It's obvious that you've put a lot of work into this. You should definitely keep writing music!