Never go to a birthday party if you got invited

I have aging off and I've truly lost count of how many birthday party invites I got in the last gaming session. It's insane. And it really lacks any kind of logic, because it shouldn't even be an option unless the sim is seriously going to age. If the sim is far from growing up and his/her time has not come yet, why in the world would the game chose this (especially with aging OFF)?