Mum naming her new dog our baby name

For context we are pregnant with our second child, a boy this time. We are absolutely set on a boy name and have been set on this name since being pregnant with our first (but she’s a girl so didn’t use the name).

We then decided on a girls name with our first being Imogen - “Immy” nickname. Stupidly told my mum this and she ruined the name for us by constantly referring to our unborn child as Immy more than we had. Not a big deal and not intentional but it just put us off and felt weird so we ended up changing name last minute.

This time we decided we would keep the name completely secret to avoid any of the same issues.

My mum about 2 weeks ago randomly decided she would be getting a new dog (male), all very impulsive. She told us some of the name ideas being Asher and Cosmo (pretty dog-like names imo). Our family dog names were also Zook and Kofi, so very unique. I didn’t think there would be any concern at all that she’d be using our baby name.

This morning, I asked her what name she’s decided and it’s our baby name. It’s quite a unique name and imo a very human like name, never heard a dog with the name and it’s very different to her previous suggestions. It all just feels very bizarre and surprising.

Anyway, she hasn’t got the dog yet and won’t be collecting it for another 2 weeks so I stupidly assumed she would just offer to change the dogs name when I told her it’s our baby name. Instead she is refusing to, said she has already ‘registered the dogs name’ and is moaning to family about how sad she is because she feels like she’s not even allowed to name her dog what she wants.. she’s saying it’s all my fault for keeping the name a secret and it’s too late to change now.

I am honestly furious and so upset, we don’t like any other names and are so set on this one.

Looking for any advice please and maybe some clarity - am I being dramatic or am I justified in feeling upset?