How much trouble would I get in if I carried a stun gun at the age of 15 in maine?

Alright...I am 15 and I live in maine. I want to get a stun gun or a knuckle blaster which is kinda like br knuckles accept they are legal and they are like a stun gun. But I don't know how much trouble I would get in for carrying it. The only reason I want it is to protect myself. But what happens if I get into a fight with someone who has a bat or something...what the hell am I supposed to do?