I've been dealing with a similar issue -- I'm due 10 April and my mom wants to come over from the States as soon as possible after. I think she would be semi-helpful, but she is also a total handful to deal with, and I know I just won't have the energy. I told her several times that we wanted some time to ourselves after but she kept making plans to come right away. Finally I had to really put my foot down and insist they not come until end of May at the earliest. She didn't like it, but once she knew we were saying the same thing to all the grandparents, she accepted it.
I feel guilty because I know a lot of women love having their mothers at the birth, or taking care of them after, and I feel bad that I just want my mom to stay away. But realistically, we just don't have that kind of relationship unfortunately (though she has been much more supportive the past few weeks and I'm hoping maybe all this will bring us closer together).
Anyway, whatever you decide, don't be afraid to really stick to your guns and ask people to respect your wishes. You know best what will work for you.