Just got an Ultimatum from my(34M) Gf (28F)

We've been having the discussion over the past 7 years and my stance has always been pretty firm while she kept saying : For you, I wouldn't mind not having children.

Well, guess what, in the end.... She wants kids. As in it's a kid or IM wasting 7 years of life we built together.. all my fault for not doing this..

I guess I'm at a loss for words.... Any advice?

EDIT : Thanks to everyone who took the time to reply and gave me some pretty good advice .. I guess I already knew the outcome.. just didn't want to go through with it.