The saddles refer to the patches of red that go along the snake's back, and the banding is the white between them. I would agree that it looks like an amel with particularly wide banding, probably produced by line breeding.

While I wouldn't consider myself an expert at aging corn snakes, I could easily believe this one is three months old.

As for its neck; looks perfectly normal to me. Corns have quite a pronounced break between head and neck that makes their neck look skinny, and its particularly obvious in young ones as the head is 'oversized' compared to the body. As it grows it'll grow into its head and its neck will start looking more proportional