Why does my cat always want in my bedroom?

i never had a problem with it until i had my daughter but now she just sneaks in alll the time. and if my daughter is napping in my room like she always does, i can never leave her in there to go do the dishes or do laundry or whatever.. my cat always runs under my bed when i try to kick her out, and just stays under there until i go to sleep. its pretty annoying