It's very nice that you've made a room specifically for your bunny and kitten. Not everyone has that opportunity.

But own room or not... an un spayed female will yowl. And it's not a cute little meow. It's loud and annoying and they off course howl at all hours of the night when you are trying to sleep.

Before I got my female cat fixed, she was in heat for two weeks straight. She howled all night, every night. I can't imagine anyone voluntarily living with an animal that does that.

And males spray. Females can spray too. That kitty room will reek to high heaven.

In a year or two, perhaps your mom will understand.