Sis in Law Driving Me Nuts!!

So first off I'm a FTM and I'm already feeling super protective and jealous of my baby and she's not even here yet. My sister in law has two little girls that are both under 12 years old and not well behaved at all (not just my opinion, everyone thinks this). Since the moment I told them we are having a baby, every single conversation I have had with my sister in law has involved her telling me how her girls just loooove babies and are going to come see and hold the baby in the hospital, and how they keep telling her they're going to hold her at every family event they can think of. I'm glad they're so excited, don't get me wrong, but I just don't appreciate people TELLING me what they are and aren't going to do with my baby. I dont want to start any problems but GEEZE! Am I wrong for feeling this way?!