you need a uci license...... im assuming your over 18.... so thatl be 60 quid... (im under 18 so its half price)
you get given your team tracksuit and riding top... which you have to wear at european champs and world champs... but NOT world cups... i recommend starting with the world cups next year.. they are the most enjoyable... we always have a laugh at them.. and the sections will be good..
i doubt you will want to do the worlds next year as its in new zealand...
if your doing it i would get practising.... i had a shock when i rode my first uci event... but my level hasbeen brought up so much since then because i know what to train etc etc
EDIT: just seen your edit
youl ride with kenny and vince etc.. but everyone rides the same route at world cups no matter what age...
so even though im 16 i still compete against vince etc etc... even though they dont ride qualifcation because they are in the top 8..
there is 2 world championships..
youth games
and world champs
at youth games there is the cadet, minime, benjamin.. all the little kids categories.. which is what i rode this year..
world champs : junior and elite only... next year will be in new zealand... so i recommend sarting off by doing a couple of the world cups before you get into it...