When I get older, I understand.

 The older I grow, the more I understand my parents—why they said what they said, why they told me what they told me, and why they did what they did.

I used to be so headstrong. I used to think that they didn't understand. Little did I know that it is me who didn't understand. 

We young people like to tell our parents that they don't get it. We think that we know everything. We think that they don't understand. It is only when we go through things, go through life and grow older that we understand that they got it. It is us who didn't get it all along.