K.D.
As far as going out on New Year's Eve - I think all parents are concerned for their children's safety. NYE is known for drunk drivers and not to mention the roads were bad because of the snow storm. My parents have always worried about me (I'm 35 and live 2000 miles from them) and will check on me when they know I've been out late or have to drive in bad weather. You're still her little girl, so I don't think worrying about you will ever change. Also she probably doesn't yet trust you in doing what's right for your son and feels the need to step in and be overly helpful. Sounds like she's driving you crazy and if you want to sustain a relationship with her then you should distance yourself as soon as possible. It will be a lot less of a stress on you once you have moved out and can parent your child the way you want (although Grandparents will still always spoil when you go visit).
After reading your response, I just want to add something. You asked what the other mothers do to be able to stay at home AND have their own place. . .well I can tell you that it took MANY years of hard work and savings to be able to afford that luxury for me (and I would assume many of the others here). And even now, I still work part time to help with the bills. Get a job and stop expecting the world to be handed to you on a silver platter. I promise your mom will start respecting you a lot more for it. Sorry to be harsh, but it's reality that we have to work in life in order to be able to support our families.