Moms are embarrassing

My poor third-grader. One moment I think he's appreciative of me (see prior post) and the next moment I realize that I've embarrassed him, maybe even shamed him, among his peers.

Let me explain:
The preschooler was complaining that he has to sit in a booster seat -- after all, he's five and why wasn't I properly respectful of that fact. So I told him what every mom would, "In a year or two, you'll be out of it. This is the best way for me to keep you safe..." He's just hearing "yada, yada, yada."

The third-grader couldn't contain himself: "A year or two! I just got out of a booster seat!"
He did? I can't remember. It seems like ages ago. But sure enough, the third-grader went on to tell the tale of the beginning of third grade when the teacher took a poll of the class to see who was still in a car seat of some sort (She had nonjudgemental wording, but I can't remember it. And really, are the words "car seat" or "booster seat" judgemental? Apparently to third graders.)

"I was the ONLY one, Mom!" said the shamed third-grader. "I had to hide in the back of the classroom and raise my hand..."

How do I explain that he's the first born and he's not going to get to do anything fun at an early age while his brother will be smoking and drinking before he's 12? (Not really in case you are planning on reporting me.)