It depends on the person. I lost a lot of my riding buddies through my teen years, they were discovering boys, partying and alcohol and forgot about horses. Horses 'weren't cool' in high school.
The only time I didn't ride through my teen years, was when I was finishing my final year of high school, the last 6 months I put my horse out to spell so I could focus on school work. After that, I got straight back into it.
I'm currently 16 and ride every 2 weeks. (I ride more often in the summer though). Once in a while I'll be heading to the barn and I'll tell myself: wHy do I like horses so much? WHy do I spend so much money on this sport? I could have this and this that I want soo bad if I didn't spend all my money on horse stuff...
And then I have my riding lesson and I tell myself after it... KaaaaY, I was STUPID for even asking myself that question!
I wouldn't stop riding. You'll get through it. ;) We all go through phases like that. :)
I'm at that age, but I have the opposite circumstance, I love riding even more! I would ask your teacher/instructor/trainer, if you could make lessons more fun? If you have space to ride at your own home, maybe the things you played/enjoyed in lessons could be used at home?