It’s a Catholic answer I’ve seen many times on this forum. I may not be Catholic anymore, but I used to be a good Catholic who thoroughly studied the faith.
People are not obligated to reverse vasectomies or tubals after they confess them.
Having had a tubal when you weren’t Catholic and didn’t know it was wrong/sincerely believed it was a good thing probably would mean it wasn’t a mortal sin, but later when you become Catholic you can still repent and confess it. Either way, whether it was a mortal sin or not, the Church would not require you to reverse it.
(Though of course you may want to if you want more children.)