My mom…

Well, for what I see, your mom thinks of you as a child, still. She probably doesn't want to lose you, so she makes all of those crazy stuff so you will never leave her. You could try reassuring her that you are there, that you are going to continue there, and that you're not going to leave her. Tell her how much you would like going outside and hanging out with people your age, and that if affects you a lot that you cannot go. It will probably take a little pushing from your side, but she will eventually get you. Explain the whole situation to your sister, too, and ask her help.

12 year old having mother problems, surprise. If you're twelve, you're twelve, deal with it. As you get older, you could have genuine ground to say something, but now you're twelve.

The bed thing does seem odd though, may want to bring that up at some point.

well I don't recommend this but if you have a serious talk about this with your mom dosent give you reasonable freedom and rights then I promise you you HAVE TO become rebellious not like bad rebellious just take your basic rights back