Welcome!
I'll give you a run down of the classes.
Warriors - your tank n spank class, most safest class to play but don't come into their own until level 44+ Quite hard to level. Expensive to kit up for lategame, but amazing if you do manage it. Relatively decent solo class, no troubles doing bit of everything.
Wizards - least safest class, you'll likely die a lot need to pay close attention to shield/health, but very rewarding for cash hunting (makes the most gold out of all classes) and mass aoe clearing of mobs. Easy to level, becomes really strong once you hit level 45+. Probably worst solo class, definitely scarier when in packs.
Taoists - Best utility out of any class, provides nice buffs and at 43 get poison cloud which is their bread and butter lvling/boss killing spell. More of a supportive role, quite difficult to master, decent at cash hunting. Amazing solo class, but shine best when with another class.
Assassins - Probably the most fun class to play if you enjoy PK or PvP at the moment, due to invisiblity/DoS, but also quite squishy and so difficult to stay alive at times. The best solo class by far if you just want to do your own thing.
