Defensive strike?

[Chocolate Muffin's]

I would consider him a juvenile until he is about 700-1000 grams and about a year old, then he is a sub adult. Also a nippy young snake is a common occurrence and WILL go away over time. As long as the husbandry is right and you don't stress him out, he will get used to you and the feeding schedule. Most snakes are smart enough to realize humans are not here to harm, but some get confused with food and human.

Agree - also, if you feed in his enclouse becareful. He may associate your hand with food and tag you accidentally. A lot of folks may advise you to feed outside of the enclosure in a seprate feeding bin, if you are not already doing so, because he is young and nippy. They usually do grow out of it, with the exception of it being their personality, but thats rare.
That's another reason the animal's husbandry is soooo important because these snakes get stressed out very easily, and improper temps or humidity can make their behavior troublesome. Your asking the right questions