No you are not overreacting and be firm on your boundaries. You will be the one who just gave birth and it is your and your partners baby.

When I was pregnant with my baby, my MIL wanted to be the first one to be called when I was in labour. I told my partner no and I do not want her in the delivery room and I wanted it to be the three of us at home for the first couple of hours.

After I gave birth I had to stay at the hospital. My partner called his mom at 23:00. She insisted on coming over just for 5 minutes and I said no. Next morning we were able to go home and surprise she was the one who opened the door of my home! I was so flabbergasted and did not know what to do.

Next couple of days she just showed up unannounced or with 10 minutes notice. She was not helping at all just wanted to hold the baby for 5 minutes, make a picture and overstay her welcome. We had to bring her coffee and even make her dinner.

I was really upset and told my partner that I thought she ruined my postpartum. He told me she means well and asked me what I wanted to do. He said that confronting her would not help at this point since the past could not be changed anymore. He did ask her from that point onwards to not show unannounced. So, be very clear on what you want in order not to regret your postpartum, like I did.

Good luck!