Hey.. i'm only 19.. so I can sorta relate. If you intend to do worlds, you'll be in a draft legal race, hence I'd get a pair of profile jammers, or cinelli spinicis (s/p?) instead of full out tri bars, which wouldn't be legal anyhow. For wheels, I'd take two pairs, probably the mavic cosmos as a training wheel and the vector pros as race/back up wheels (or the most durable wheels for training, and lightest wheels for racing). For the tires, and tubes, I don't know the prices, but I ride Axial pros on my training wheels, and I have some tubulars for my race wheels. When i replace the tires, i'm gonna get some conti 1000's because they're super cheap here (Canada), but thats a pretty presonal decision.
Run kit-I have both training shoes, and race flats, if you have the money, IMHO get race flats. For training I have 1 dry fit top, which I wash alot, but I think its alot better than cotton.
Racing- last year at Jr. Nats I borrowed someones aquablade top, but this year I'm getting a Sugoi tri top, and on the bottom I just wore speedo jammers. This year I've gotton some Aquablade jammers, and thats what I intend to race in. If the bike portion isn't that long, this setup works well.
Cycle - just get some decent shorts, thats all, a jerseys nice but I'd spend the money of shorts first.
Wonder gadgets - umm.. race belts and speed laces are nice little things which help save time, a gel flask maybe, but I just tape a gel to my top tube.
Good luck and have fun, and remember - SWIM.. thats the best thing that you can do to get better, (and if you can't swim well.. forget doing well in a drafting race, that was a very interesting lessons which I learned at Nats)