I'd imagine his first "adventures" would be Rugrats-like in that they're all the products of his imagination. They'd probably all be centered around his mother's restaurant.
Like fighting ice monsters the first time his mother asks him to venture into the deep freezer for something.
Make believe things like that when he's helping get things ready for the day, or cleaning, or what have you.
He starts getting his first real taste of adventure when his dad brings him to work with him to the central "office" (The Teacup) where the Justice /co/mrades have their base of operations.
There he meets supers of all types and starts learning things, like how to make traps and MacGyver things from an old veteran hero.
Then comes the application of these skills in the babysitting adventures and duels with Tats, who everyone jokes as being his first nemesis.
Now that his skills are polished a little, he starts venturing out a bit more, probably meets Alpha, the boy robot, and looks up to him like a big brother/mentor. All of this is taking place on the floating island.
So here is where he needs to begin getting more friends about his age range. Based on past chatter, this is about when Deelette would spend her first summer vacation on the floating island, adding another member to the "gang".
Once he has a proper crew/team/gang, then he's ready to start getting up to real shenanigans with magic cookbooks, foiling dark chefs, entering cooking contests, and whatever other ideas we can think up.