Anyone else get this from family/in laws?

I've been wanting a baby since I got married. My brother, cousins, and in laws all let me watch their kids from time to time and they make me exhausted. They are so much fun to play with and we have a blast playing. I put my all into making their day with me fun. Some can be challenging, like some that won't sit down to have their snack or asks a million questions I'm not sure it is my place to answer, but it is still fun.
Once they get back for their kids and I tell them how tired I am I get "You still want kids?" It takes everything I have to not scream in their faces, "Just because your kid acts like that, doesn't mean mine will." Every one teaches and disciplines their kids differently and it's not my place to teach or discipline them the way I would. They aren't mine. My kids could be completely different. I want to teach them that it is ok to be scared of things and some of those scary things make them braver later in life. I want to be able to take my kids outside with a parent say no, just let them watch cartoons. I want to answer their questions as honestly as I can but still leave things out that I think they need to learn when they are older. 
I want my own baby more then anything. Your kids are yours and I love them, but don't try to talk me out of something I have dreamed about.