The only advice I could give to a beginner, is to start with a custom character. I would not take an origin for the first run. Firstly, because the origins all have some weird quirk in their backstory which you might not like, whereas for a custom character you make up your own backstory entirely. Secondly, when I played an origin (Karlach) it was much less satisfying than having Karlacjh around as companion, as you miss out all her preset responses and banter. So, my experience is that the origin you play youself comes out poorer than as a companion.
Apart from this, I don't think it is very useful to give you "my" preference. I think you should consider some obvious personal preferences : Would you want to lead in battle and use priomarily melee attacks ? Or are you a magic enthusiast ? Or do you want to be able to use both in a supporting role for the frontline tank ? As for races. Same, take the one you feel most comfortable with.
Then go out and see if it works out as you expected or not. With all you leanred on the way you can restart a campaign with a different race/class combo. I expect that to be the way it went for the majority of new players.
