Do better in school.
Concentration, aggravation and kerplunk.
When I was 16 I was dating my future husband, Dale. Let's just say he was pleasant distraction with unpleasant academic results.
I graduated from college with a 3.0 ( as well as husband, three children, a job and a mortgage) but graduated from high school with a barely a 2.0. In high school, I got good grades in my favorite subjects, English, literature, French and writing classes but passed math and science by the skin of my teeth. Not to mention that skipping my afternoon French class to go see Dale at his high school brought my excellent grades down, too.
It made me think I could have done better in high school if I'd have applied myself and been less distracted. No one's fault but my own.