I really do think it depends on the child. Such as I may have Harry at this birth, but I know that he will assume the role of a support person himself. Whenever mum is upset or in pain, he lies next to me and strokes my hair and face, maintains eye contact and becomes an amazingly stable rock. He's been like that since he was 2yo. So I don't think its too young, just really depends on their learned behaviours and exposition to such things as pain and panic.

Think back to how bub has handled situations in which you were upset or hurt. It might help give you an idea of how they will cope.