AITA for refusing to let my mother-in-law babysit after she tried to sneak my baby to church for a secret baptism?

I (30F) have a six-month-old baby girl with my husband (32M). We are not religious, and we both agreed we wouldn’t baptize our child. My MIL, however, is very religious and has been pushing for a baptism since the day our daughter was born. We’ve told her multiple times that it’s not happening.

Last weekend, MIL offered to babysit so we could have a date night. She’s watched our daughter a couple of times before with no issues, so I didn’t think much of it. We were out for about two hours when I got a weird feeling and decided to check the baby monitor app on my phone. It connects to a camera in the nursery, but when I pulled it up, the crib was empty.

I immediately called MIL, and she didn’t pick up. I called again—no answer. At this point, I was panicking. My husband and I rushed to her house, but she wasn’t there either. After about 20 minutes, she finally called me back and casually told me she had taken my baby to church for a "quick blessing."

I lost it. I told her she had no right to take my child anywhere without telling me, especially not to a church for something we explicitly said no to. She tried to justify it, saying she was "saving our daughter’s soul" and that we’d “thank her one day.”

I told her she would never be babysitting again. She freaked out, saying I was being unfair and overreacting. My husband backed me up, but now the whole family is against us. They’re saying I’m being “cruel” for banning a grandmother from babysitting over “just a blessing.” Some even said I should be “grateful” that she cares so much.

I don’t care—I feel completely violated. But now I’m wondering, am I overreacting? AITA?