I'm going to graduate high-school with PRs of 49 in the 400 and 1:55 in the 800.
I also run cross country my PR is 16:44 for 5K.
Everybody tells me that I am more of a 4/8 guy, but I really feel that my best distance would be the marathon.
During XC season, I can keep up with the best guys on my team for 14 or 15 miles, but I am just not as good at the 5K.
Is 18 too young to start marathon training, should I just focus on the 400 and 800 until I'm done with college?