Taught my nephew Catan last month and he beat me on his third game
I set up a four player game at my sister's place in Boise last month and figured I would go easy on my 12 year old nephew for his first few rounds. He lost badly twice, asked a bunch of questions about trading, then on game three he cut off my wood supply and ran away with it 10 to 6. How young were your kids or nieces and nephews when they started beating you at your own games?
Oh man, been there! My oldest was 13 when she finally took me down in Ticket to Ride, and I swear she had been quietly studying my routes the whole time. What got me was how fast your nephew picked up on trading, that's the part that usually takes kids forever to figure out. My daughter did the same thing, lost a few games, asked a million questions, then just flipped a switch and started blocking my trains every chance she got. Now she beats me about half the time and I can't even pretend I'm letting her win. Kids are scary good at picking up game sense once it clicks for them.