@BL4Z3453 It's good and I like the concept a lot. I'd change being a vigilante at 5 to him training his quirk privately until he is a bit older then maybe around the 9-10 age range he starts being a vigilante.
But that's me and this is your story concept, I struggle with the viability of a 5-year-old fighting grown adults even with a quirk. I find the 9-10-year range a good start because the quirk levels the playing field at that point. and he'd be old enough that he's not still just figuring out the world.
