People trying to make me feel guilty for getting a pitbull-please help!!

People are making me feel bad that I bought a pitbull. I have a 4 year old daughter, so I think they think I am being an irresponsible parent, and they are saying "enjoy her playfullness now because she is going to turn on you" We are not mean to her and I would never teach her to be mean. What should I say to these people?