My milk tooth has been loose for 12 years and still won’t fall out

I still have a canine tooth on the upper jaw that refuses to fall. It started moving when i was 8 (currently I'm 20). Most of my milk teeth were removed at the dentist because they wouldn't fall on their own. But this was the last of the bunch, and i was already pretty traumatized so i never really went back to the dentist regarding this issue. I remember them telling that I'll probably need a surgery because the tooth above it had already grown. I have moderate crowding in my jaw. I'm now looking forward to get my over crowding corrected.
That's why i was wondering why has my tooth not fallen off even after 12yrs? It moves quite a lot but doesn't fall off. Is there some serious issue?