Maybe if Tony knew how to handle that thanks more gracefully, he wouldn't have to argue, "The age thing is stupid." In fact, he thought it was stupid enough that they had swiftly moved passed it and it wouldn't occur to either of them again. He opened his hand in disbelief to express this. "You already said you were his best friend. If that imbalance is so significant, you should back off, let him connect with someone his own age so his brain can develop or whatever it is you're concerned about. You've already crossed that boundary."