Yeah, I just started a new game, and somehow a gnome was right in front of me, and attacked me before I did anything. Looks like the monsters go first, or the monsters get a free turn before you or something, but regardless, I thought that was interesting to know.
The player is always first in a turn. You probably walked onto a tile parallel to the tile the gnome was standing on, so he could attack you... or maybe you accidentally pressed space which counts as a turn.
I was actually tabbed out, not touching the game at all, waiting for it to load. that takes a while on my computer for some reason.
I think that the player's first turn is counted as his/her stepping off the stairs and entering the dungeon, thus all the monsters act once "for free" at the beginning of the game. I just made the above comment because I couldn't resist.
Add to the second level of the skill that the first turn of the game you get to go before the monsters.