Starfish - you don't have to be fast, just tenacious and we all know that you're that!! You could totally do a tri. You would swim well and be comfortable in the water, get out and bike the best you can which would be just fine and relax on the run, enjoy the scenery, cheer people on and walk /jog your way in. Done. No problem.

Really you could do it. You need to read "Slow Fat Triathlete."