Vent/Rant/Argument

I had a huge argument with my mum because there was an accident while my partner was bathing our 3month old he put him on his changing board after bathtime & baby slipped off the board & into the tub. My partner was worried he came & told me what happened so we took baby to get his head checked just in case. Our son was settled throught the day so i knew he was okay & the doctor told us his head is fine everything is alright there's nothing to worry about.

I told my partner to be very careful and don't let it happen again, later on in the night my mum was holding baby & i told her what happened..she got so mad & started calling my partner names, like useless father, dumb ass parent, dickhead ect, i came to defend my partner & told her she has no right calling him names and he already feels bad enough about what happened but she kept saying he's a dick he dropped him, i said no he didnt drop him, he slipped, it was an accident & we're lucky baby is fine, she said it doesnt matter hes still a dick and she continued shouting it out while holding our son and i told her you're being disrespectful, dont hold our son and disrespect his father, she told me you need me, your nothing without me, your not even a mother, your not even a parent

that really hurt me, to hear those words from my own mum, I look after my son, im with my son 24/7 i make sure hes got all his needs before me, i put him first, i take him to his dr appointments on time, make sure hes fed, changed has a bunch of clothes i love him more than anything so to hear those words really broke me. we haven't talked since that night..

i dont want anyone talking down on my parenting i know im a good ass mother but i just dont know how to talk to my mum..she expects me to apologize but i feel im not wrong ..am i wrong?