My Grandson!!!?

So, last night was father/son night for me and Morgan. We went to a local place called Li'l Biggs, which has a game room for kids and all you can eat greasy pizza. It's pretty inexpensive and there are a lot of games for kids to play. Morgan loved the giant sandbox, skeeball...and the giant jumper room. So, Morgan bounds out of the jumper room and picks up a toy guitar and pretends to start playing it. (He loves playing his toy guitar at home.) Only, I wasn't sure if the toy was part of the game room or if some kid brought it. So I turned to a lady, whom I would guess to be in her late 40's/early 50's and ask: "Is this part of the gameroom? Is he allowed to play with that?" "Yes, the kids can just pick up any of these toys and play with them," she answered with a smile. A cordial, quick conversation, right? Then she hits me with this: "So...how many grandchildren do you have?" What!!?? Did you just call me a grandfather? Heck, I know my age is catching up on me, but geez...grandpa!??? "This is my son," I answered, "and I have another one on the way...due next month." Then I abruptly turned my back to her and walked away. What the...? RUDE!