Q: Am I bad selfish, daughter if I don't want my mother to move in with me, my husband and our two children?
A: In an ideal world, we'd all have unlimited money, health, time, and energy—enough to do all the things we want to do. In the real world, there are rarely enough resources to go around, so we spend a lot of effort trying to balance needs and responsibilities according to our values and beliefs.
It would be nice to think that it's always possible to work out a painless compromise, but that really isn't always the case. More often than not, to give to one you must take from another.
From the way you word your question, your primary focus right now seems to be your husband and children, and the life you have together. You believe that adding your mother to the mix would disrupt the life you've worked to build, but you also seem conflicted about choosing which of your responsibilities should get priority right now.
Only you can decide what's right for you, given your particular history and circumstances, and what works for you might be different than what would work for your friends or siblings. Not wanting you mother to disrupt your family's life isn't selfish—but it may be something you need to explore with a therapist, clergy, or trusted friend to air your feelings and feel comfortable with your decision.