Thoughts on an issue...?

My fiance and I just had a baby 2 months ago. We are thinking about moving...possibly out of state. If not, definitely out of this city. My parents live in the next town over about 20 minutes away. Everytime I talk to my mom about moving (I've told her about it before when we considered it a while ago) she actually gets MAD at me, and makes me feel guilty about leaving, not only because all her other kids moved away, but because she won't see her granddaughter as often. She only has 2 other grandchildren and they live in Boston. (We are in Ca.) Then tells me it's my life and do whatever I want (not in a nice way!) But when I look at the big picture, I have MY OWN family now and shouldn't feel guilty about leaving...right? And I shouldn't stay somewhere I don't want to be..for her sake. I don't think its fair and I'd hate to suddenly go to my mom and say "Hey, we're moving" but she makes it that way because I can't talk to her about it before it's a done deal. Thoughts on this? Or advice on how to tell her we want to move...without making her mad