Right now I am playing as warrior going to take dragoon path. But this is not my main character. It is more like a test character. So, right now I cant decide whether I should choose wizard or archer for my other character. My mind are so confused right now. Lol 
What are you looking for ?
I am looking for a class that can deal a decent dps and also not so squishy as I very often play solo. Might prioritize for PvE though. Right now my swordsman are quite tanky but the damage output are not so high.
a; it doesn’t matter. there is no “best” character. play what you think you will have fun playing.
b; do research first, because if you don’t, you will regret it later.
check the class forums. check the ToS wiki’s on the web. watch gameplay videos. heck, just watch other players as you level. use all of that to decide what you think will be fun.
you have 4 character slots to start with, and the slots are permanent – if you delete a character, you still have an empty slot you can make a new character in, so don’t be afraid to experiment.
it’s also best to try to focus on a single main character. the more you spread out over several different characters, the slower each of them will level.