For young children it is primarily experience that determines character. For the adult it is character that determines experience. That is, the ego is initially built on experience, and later builds experience. Thus the elderly fear change because they have something to lose; while the young are still building, and have everything to gain. Children are therefore curious and open; they are not afraid to ask questions precisely because they do not fear ignorance.
But children become adults, and soon the feelers of abstract thought grow and reach out, bringing a new knowledge, a great knowledge, and great fears also. Soon, everything becomes fearful, and they too will be heard barking, even when the wind rustles through the grasses.
What is it to be a child? A child is one who sees adults as mad. Thus, when you find the people of this world acceptable, you have grown up. It is better to have more of the adolescent in you than the "mature". Strictly speaking, maturity indicates the end of growth, both physically and mentally. If you're green you're growing; if you're ripe, your rotting.