My stepdaughter likes to pick up little Noah by the back of the neck, he is about 4 and half months old and I think he is too old for this. What do you think?
I agree with you. I think that, with the exception of the Mother cat and trained veterinary staff when necessary, a kitten or cat should never be picked up this way. Not only could it be physically traumatic, but it's not the greatest way to influence a kitten to become a calm, loving, confident, but gentle cat.
You most often get from a cat what you give and if you want a calm, gentle, loving, non-aggressive, non-fearful cat, you need to treat them from day 1 in the most gentle, calm, loving, non-threatening way and that would exclude picking them up by the scruff. Leave that for the Mom and, as I mentioned, the veterinary staff when they sometimes have to restrain a cat momentarily by holding its scruff. Even then, we don't pick it up unsupported by the scruff. We may just hold the scruff while the kitty is sitting on the exam table if we need to obtain blood or give fluids, etc.
Thank you for asking. What a cutie! Enjoy!