What does this poem tell us?

"Encouraging Learning" is an ancient poem by Yan Zhenqing, a poet in the Tang Dynasty. It is only 28 words long and tells a profound truth.

This poem warns teenagers to cherish their youth and learn how to study hard and make a difference while they are young. Otherwise, it will be too late for them to learn and regret when they are old. We should cherish the time. Let children understand that life is short, so as to improve their enthusiasm for learning.