Please look up something called post tubal ligation syndrome. I wad having misgivings about having my tubes tied & a few ladies on here warned me about what can happen. After doing some research, my dh & I have decided to cancel my procedure because we don't want to take a chance that I may be one who is unfortunate enough to have issues.
Don't take your choice away. Make him get snipped. You are way to young to consider getting your tube tied. Plus everyone I have ever spoken to who had tube tied said it made their periods worse. Really think hard about it. I am 37 pregnant with my 3rd child. After this one is born my husband is getting vasectomy.
There's lot of young girls in the 18-24yr old forum contemplating this too. Not meaning to be rude but I do think age does play a role in your decision and also the drs willingness to do it. Despite me age, my drvwont do it incase this one is prem like my first but doesn't make it (I'm high risk). If your dr does say no, you might like to consider a long term contraceptive and that would also be less invasive then having your tubes tied. Good luck with your decision!