Tubal ligation

I just heard that you can't get your tubes tied after vaginal birth because there's a chance it might fail which is rare. They suggest do it on my 6 weeks pp unless I have a c section then they'll do it right then. Is this only the hospital I'm going to or every hospitals that do this? I just want it done after this baby, no more kids for me. Due 12/12 can't hardly wait.