You had a lesson(D)

Tranquil as a baby and good fun as a son,
Adolescent starts learning, how much quicker it's become,

But there's a danger inherent in learning too fast
that the pupil starts teaching the teacher,
But the knowledge he's gained has come from the past
and his teacher knows less than a preacher,
And you learn as you turn on the planet that formed you,
Before you get to be very much older,
That it's the weight of doubt that is bringing you down,
not the weight of the world on your shoulder.