Suited for sprint or distance - how to tell?

How do you determine whether you would be better off training and racing sprints or distance events? I'm back into competitive training this winter after ~2 decades since high school. I used to coach age group, and I've been hitting some master's practices, so I'm not without direction for what I should be doing to get back in shape. I am, however, clueless about distance swimming. I have no exposure to distance racing or training so I am starting to read up on it (Maglischo). In high school, with the longest event being the 500 free, everyone was a "sprinter" whether they were suited to it or not. Since I'm basically rebuilding myself from the ground up, I am wondering whether I might give distance a try? What sorts of physiology, technique or psychology lend themselves to doing distance as opposed to sprinting? Or does this not really matter for a nearly 40-year-old masters swimmer that's been out of the pool for nearly forever?