Here there is a story about a mother who never pays for a bus ticket for her son, saying he is too young, even though he isn't. The boy is ashamed to be treated like a baby and he tries different ways to assert himself. In discussing this story I'm having a few problems.

If I want to say, "She doesn't want to admit that he isn't a baby anymore." is it Она не хочет признаться, что он больше не ребёнком. Should ребёнок be in the instrumental here?

What about она всегда сказала, что он ещё не учником. Is this correct?

To say, "He isn't that young.", should it be Он не так молод or Он не так молодой?

Thanks for any help,
Z