Did I overstep?

Everyone in my husband's family likes to pick on him. They act like he is still the same irresponsible, immature, kid he was when he was younger, who wasn't going to amount to much. When in reality, he is one of the only people in his family who is actually doing something with his life.

He loves to play with his nieces and nephews and it definitely brings out the little kid in him when he does. Well, last night we had a big family get together and he was crawling around on the floor playing with the kids. Then his grandma makes a comment about how it's a good thing he doesn't have any kids, he's too irresponsible to be a dad, and asks me if I really want to put up with this for the rest of my life. I just looked at her with a blank expression and said, "that's a really shitty thing to say". Now keep in mind, I am usually a really quiet person, especially around his family, and don't tend to speak up, but what she said really pissed me off. She's kind of a bitch and makes really rude, snarky comments all the time and I always let it slide, but this one crossed a line.

He and I have been TTC for 3 years and went through a miscarriage during this time. I would not have married him, nor be trying to have a baby with him, if I did not think he would make a damn good dad! I mean, a man who is willing to get down on the floor and look like a complete fool, to play with some kids, that's who you want as the father of your children! Am I wrong??

Now the whole family is having a bitch fit because I stood up to his grandma, even though they all talk about her behind her back. Did I overstep?