I also played Rakdos at the prerelease. I went 4-2. My two losses were to Azorius (0-2) and a guy who signed up for Izzet, but his deck was Azorius with a couple of burn spells (0-2).
As for getting back into MTG, I recommend starting with draft and/or sealed events. You will relearn the rules, and while you may play against competitive opponents, you will not be playing against the Tier 1 competitive decks you might see at a constructed event.