I thought Tsuna was 15 and 5'5?
Tsuna's school performance[edit source]
There's something that bothers me a bit: After the first fight with Mukuro Rokudo, where Tsuna goes the first time into Hyper Dying Will Mode (HDWM) and collapses because of the muscle aches, Reborn says something like Tsuna will get sore muscles because he went into the HDWM with his low stamina. But later, we never see him having sore muscles after a fight. Now I wonder if Tsuna is as bad in PE as at the beginning of the series.
The same goes for other subjects. Hey, he saw so much weird stuff and had to solve problems which determined the destiny of the whole world, homework or an exam should be nothing. And his right hand is Gokudera, who almost always has full score. And Reborn know well how to let Tsuna undestand something. Is his school performance still "no good"? (Extra: And what about bullies? Shouldn't it be easy for Tsuna to defend himself at least a little bit? I know he doesn't want to hurt "civilists", but fleeing, which should be easy for him, is ok, or not?)