well, i wouldn't expect not having extra weight to slow you down. seems like it would speed you up. that would give you an advantage against bigger guys. But i'd still throw a nice elbow to your ribs.
I'm 27, and have been above 200 since high school. but i think my metabloism actually helped me, cause i was a fat kid in middle school. Then i hit my growth spurt and my metabloism sped up. I stayed about the same weight, but streteched out. Then gradually put on more weight when working out (i wasn't 200 pounds in middle school).