Some advice for a newbie (avoid spoilers please)

Greetings,

I am playing the game for the first time, used to RPG's though (Dragon age, mass effect f.e)

For the first quest with the free beautiful witches (cough) - I freed the tree spirit thing cause the witches seemed.... not nice. Anyways, the horse getting all red eyed did creep me out, so how impactful is this decision? I have a save to go back to if it has some crazy impact in the story. I generally try to be a good guy witcher, but of course I'll always see to get paid.

Will that decision bring me on some bad route later on?

Thanks and cheers,