Mother in law

Every single my mil says she is buying something for the baby for her house it freaks me out and overwhelmes me. She is buying a car seat for her car and play pen and other things. I know she will be baby sitting maybe once or twice a week for like 2/3 hours while I'm at school but I feel like she can borrow some of the things we have. We have an extra car base so she doesn't really need a car seat and we have a play pen she can borrow since we also have a crib. She can sometimes be over vocal and demanding and I'm afraid she will try to take over my baby. Is it just hormones? Husband thinks it is but I feel like I don't want her too involved since we almost got a divorce multiple times because she was meddling and causing too many problems in our marriage. I had to force him to move some distance and I'm afraid she will try to "teach" me how to be a mother and take over.