I think a woman should be able to choose. When I NEEDED a hysterectomy a few years ago the other consultants I went to agreed that I needed one but wouldn't do it because I was only 23 at the time. Luckily they were my 2nd and third opinions, and all I needed to know was whether it was necessary or not.
Unless medically nessescary I would say that I agree with some sort of age/child number limit.
I myself, was firmly against parenthood. Then of course in my late twenties, I fell in love, had a baby and became complete obsessed with the whole day.
To be perfectly honest, there are very few opionions that I had at 20 that are still true today. That is not a knock at 20 year olds, but the fact is there is still a lot of maturing and experiancing left to do.
There's no law on this except that a woman has to be at least 18 years old, but most doctors refuse to do it because they think young women are incapable of deciding not to have children until they're much older. I don't ever want kids and if I could I would definitely get my tubes tied right now. It's just bullsmurf that I'm 22 years old, certain I don't want kids, and I'm unable to ensure permanently that it never happens. Instead I have to use hormones that make me physically ill in order to prevent a pregnancy.