How to ask someone politely to give me space

Kenny
I'm probably going to sound horrible for saying it but my boyfriends mom is kinda taking over my pregnancy and I daren't tell her what I want if that makes sense? 
I understand she's excited and it's her first grandchild but she's picking my pram, cot and litterually everything for the baby i feel kinda shit about it because I already had the pram I wanted picked out