That's rough. But you have me a bit confused. He's not aging, but uh, if I recall correctly
your tama has to be a teen to be sent to school. Or, I'm wrong. Well, unfortunately, sometimes the captain goes down with the ship.
Your tamagotchi may have a glitch. Reset, Download, and wait till tomorrow.
This has actually happened to my tamagotchi. It was Mizutamatchi, WAY past evolution time, but I hadn't a teen on my tamagotchi! I reset, and expected it to evolve.
It didn't.
Eventually I got sick of caring for the evil glitch, so I abandoned it.
Next morning, I woke to a wonderful OBOTCHI!
So, there you go. Maybe you have a glitch, but still, your tama will catch on.
Ringo Starr