I agree with the good advice above, including starting with a custom character, though if you enjoy a darker, bloodier tale the Dark Urge may be for you. I think the origins are best experienced as companions, especially to begin with, and a custom character or Durge gives you a lot more freedom to create a character that’s yours.
The only thing you’re really stuck with is your race, as you can change class for a bit of gold and appearance at will from relatively early in the game. There are some synergies with some races’ special features and specific classes, but the game is forgiving enough especially on balanced difficulty that any race can succeed with any class. So you can just pick whatever race and class combo you think is cool. But if there’s a particular sort of class you’ve liked playing in other RPGs you might want to start with that. (Personally, pretty much every cRPG I play, my first run is as a magic user with a flavouring of rogue, then I try other options if I like the game enough to play more than once!)
But others have already said, don’t sweat it too much, give yourself permission to respec or restart, play around, experiment with tactics and have fun!
