I don't know what kind of situation you are coming from (SAHM, WAHM, Full time work at work, etc), but I know that the program I'm starting next month has told us to expect to treat grad school like a full time (40 hour per week) job. The majority of women with children in the country work, and while striking a balance between work and family is a struggle for most people, I definitely don't think having children should preclude you from doing just as well as anyone else. You can do it!
I'm a mom too, and my best advice is to create a strict schedule with your life, and if you study better out of the home, make time to do that. Grad school is tough because there is always SOMETHING that you could be doing (kind of like being a mom--isn't there always some chore you could be doing other than anything else?), but your kids will definitely remember who you are, even if you have to pull some long hours during points in the semester.
Good luck!