My MIL wants to "kidnap" my newborn?

My firstborn is almost 15. I was a single mom and I NEVER left him with anyone. I was alone in one part of the country while my family lived in the other. They came to visit but left after a week. The 1st time my son had a sitter was at the age of 5 for a few hour while I went to an interview. Then he started school.

Fast fwd to now. I'm 30 weeks pregnant. I love my DH family. His mom said the other day how they were planning on "kidnapping" the baby so I could rest. I started laughing thinking it was a joke. She was DEAD SERIOUS. I even think she got offended. She said "Well you will need to rest plus it's not really kidnapping if you know we are going to come get him!" I was like "Uh no!" I don't need a break from my newborn plus I'll be breastfeeding and my DH has 12 paid weeks of parental leave.

Not to mention my 15yo is excited and looking fwd to help plus my dad and his wife have been living with us. My father cooks at least 3 meals a day, cleans the kitchen, and grocery shops. His wife does all of our laundry, (washed, folded, ironed) and keeps the house clean. The only thing I do is clean my room and master bathroom and vacuum the house.

I know my MIL means well. Her daughter had post partum depression and she had to take care of her kids. Maybe it's a difference in culture but my grandmother had 18 kids and never had help. Am I wrong for turning her down? She feels really strong about it and is confident I will change my mind later. Even after telling her several times, she continues to say she will come and get the baby. She told my DH the other day "just call me when she's asleep" and is seriously planning on taking my newborn out of the house!

What do you think?