I used to ask myself that all the time when I was growing up. I was a horrible student all the way into the second semester of my 10th grade year! I had a difficult time concentrating in school and to be honest, there were just more important things going on in my life at the time. I have always struggled with weight issues and being bullied, teased and tormented in school was a daily battle. It's hard to concentrate on learning when survival is your priority and invisibility is your dream. I did well in high school though, and eventually graduated college with a degree in Criminal Justice.
What changed? I got involved. I had a teacher that recognized a potential in me and fostered that by inviting me to step outside my comfort zone and challenge myself. I LOVED sports. I know, sounds silly coming from the fat kid huh? I did though. I loved baseball, hockey and football the most and my teacher encouraged me to write sports stories for our school's news paper. This meant that I would have to attend the games, which I really wanted to do anyway, but it also meant that I would have to interview the student athletes. THAT was a huge hurdle for me to jump, but I did it and kept doing it! I found that the more I got out there and participated, the more respect I was given. There were still people that insulted me, but there were also people that stood up and defended me...which felt pretty good, especially when some of those people were the jocks that I NEVER would have imagined being friends with in a million years.
Once I started having less anxiety in my life, my grades improved, but it really wasn't until college that I made the jump from "ok student" to outstanding one. I really focused on my study habits (or lack there of) and began trying to find a way to study that was right for ME. What I found was that repetition worked best for me. It took longer, but I retained more of what I studied. It also helped me to talk with others about a topic or even argue with others (in a debate not a fight) because that not only opened my eyes to THEIR thoughts and ideas, but it made me more aware of my own.