Over protective ftm

So I’ll start by admitting that I’m an over protective ftm but here’s the thing, I’d rather be over protective than not care and something bad happen to my daughter.

I have a step son, he’s 7 y/o and I just had my first baby she’s going to be a month in a 5 days! Now, I don’t mind if my step son (not giving names so I’ll write him by that) holds the baby, feeds the baby, plays with the baby BUT I do have a problem when he walks around with her now my reasonings behind this is because we have a big dog who likes to play with my step son, so if he would think it’s play time and run and knock my step son over and he fall with her then what? Or if he’s walking around and knocks her head off something and lastly I’d rather her be able to support her head before he carries he around. That being said- I was in the washroom cleaning it, she was asleep in her rocker in the living room. I’m just a room away... I can hear her if anything... she started to cry and I just said to step son do you mind giving her, her soother I’m just washing my hands I’ll be right out. Alls good, but he grabbed her and was walking into the kitchen and her head is flopping around from side to side to I simply just re directed him back to the living room and had him sit... didn’t even say anything about it because I know he’s trying to be a good big brother. He just doesn’t understand that they can’t quite support there heads when they are just new. So I mentioned it to my boyfriend because in the past things have been taken very wrong and it gets twisted.. so I leave it up to my boyfriend to deal with things... I don’t intervene. Anyhow I mentioned it VERY nice too... and I just said, I don’t think step son should walk around with her just yet... maybe wait until she can support her head and he got nasty toned with me as if I were crazy and you know what? SO WHAT?! I’m not saying he can’t hold her, he can pick her up out of her chair and sit down I just don’t want him walking around the house with her while her head flies around!

Am I crazy?