It may be you're the sort that wants to go into a game cold, knowing as little as is possible. It may be that your keen to be there on day one but want all available information to guide your purchasing decision. If you're one of the latter, IGN's video of the first 15 minutes of The Witcher 3: Wild Hunt [official site] may help. It skips the introductory cutscene but picks up right after, showing the initial quests, dialogue and combat. It's embedded below and looks pretty authentic to my starting experience with most games, up to and including dying to a relatively weak mob of enemies after ten minutes.
As The Witcher 3 nears release, I find more of my skepticism about the game and series disappears. It's not that I've been convinced by the marketing or the people of the internet yelling at me, but that it's now close enough that I'm overwhelmed by my wanting it to be good. I want to slay monsters and trot around a fantasy world on a horse. I want to live in a world with functional, non-janky open worlds that aren't developed with a design ethos I find stifling.
Some (or maybe all) of the above video has been seen at press events previously, including by us. If you haven't played any of the previous games in the series, you can re-visit its good and its bad parts, or wonder whether news that the Witcher 3 is 200 hours long (if you do everything) is a good thing.