Has anyone received negativity from family?

I’m currently 5 weeks...we told our parents who are over the moon, but we told my partners sister last night thinking she was going to be so happy and she was really rude. We told her she was going to be an Aunty and she said ok...what do you want me to do a cart wheel?

We were both in shock. My partner flipped out, it was horrible.

It’s such a special time for me/us n I’m really upset I told her early now even before my brother. Feeling really anxious about it and now my partner wants to cut her out of our lives completely. I’m not one to get in to arguments and I hate confrontation but I’m just shocked by it and don’t know what to do. Wondering if anyone’s had anything similar.