Suddenly aggressive?

I've had my male baby ball python for about three weeks now. Everything's been going smoothly. I gave him the week to acclimate to his cage before handling him, he eats fine and has been docile up until about two days ago. He suddenly became aggressive and started striking at me whenever my hand gets near or anything moves at all in the cage. He is looking a bit dull and his belly is a bit pink however his eyes still look the same so I'm not sure if he's getting ready to shed or not. He's never shed while I've had him. If he is shedding could this be a reason why he's suddenly so aggressive? Or could it be something else?

That sounds like the start of a shed to me.

Yup your guy is getting
ready to shed .... If your seeing pink belly now then in the coming days (4-7) you should see his eyes get dull and hazed ... Then sometime within a weeks time from the eyes he should shed for you .... give him a humid hide or bump his humidity up to around 70% and he should give you a nice clean shed

No snakes are aggressive. They are defensive. "Aggressive" would mean they are out to get you. Where "defensive" means they want you to leave them alone.