Last week, on December 11th, I turned 40-44 years old. Okay, really, I turned 39 years old, but in terms of my age group for the 2013 triathlon season, I’ll be racing in the 40-44 year old division. That’s because USA Triathlon calculates your age group based on your age by December 31st of the racing year. By December 31, 2013, I’ll be 40. Thanks to USAT, I can cue the confetti and streamers now to mark my evolution into a new decade. Some (who shall remain nameless to protect them from having birthday cake thrown at them) have implied that perhaps …