Did anyone who had theirs out at age <30 without being in the risk group ever find out the reason why?

Maybe some of you know there is the 6f risk factor for gall stones: forty, fat, female, fertile, faint, family. I am none of these except for my mom and grandma who had theirs out at 50+. For the rest it's not even close and I had mine out at 29 because of a chronic inflammation and gall stones/sludge.
Never found out why and am still wondering.