I get overtired and I’m 33 😂
I never really had an issue with overtiredness with my boy. He just got quieter as he got more tired and went to sleep more quickly. The first time he slept through the night was at 9 months when we went to a wedding and he only had one half an hour nap and then went to bed at 11.30pm! Undertiredness is more of a thing for him - if I try to put him down to sleep and he’s not tired it will be a disaster. I guess every kid is different. But my second boy seems the same as my first. Sleeps better with less sleep/later bedtime
My nephew still can become really overtired and he is 3 years old. I think it depends on a lot of night/day factors. Even as adults can become overtired I suppose so hard to say in my opinion