My mom worries way to much. What should I do?

Last night I was in my room getting ready for bed and my nephew who is 3 keeps knocking on my door. I was being nice and told him I was going to bed in a few short minutes. I have never been a kid person but that doesn't mean I don't love him. My mom got all upset over nothing and crying because I wouldn't let him in my room. Reasons why I don't let lil' kids in my room is because some are just to destructive and gets into everything (nephew is one of them). Like I said I'm not to crazy about lil' kids and just feel uncomfortable around them. Does this make me a bad person? My mom accuses me of being hateful which I think is to extreme I mean hate is like the same meaning of murder lol! Do you think my mom is taking this way to seriously? She just doesn't understand my ways or anything. How would you feel if you had to put up with a bratty nephew every weekend and the dad keeps dumping him on MY parents to much?