Was this a bad play?

[Slow Play Ray]

Final table of a pretty weak home-game $50 freezout, 26 players. 130,000 total chips in play, 9 players remain, I have 40,000. I get KK in the big blind. Blinds are 600-1200. UTG+1 raises to 4,000, button calls, I go all-in to try and pick up the pot right there. UTG+1 folds, Button thinks for a long time and calls w/ QQ, and catches a Q on the river. Button has a lot more chips than I thought, and I find myself down to 8,000 and a bubble finish. Was it a bad move to put so many chips at stake at this point, even though I figured to be ahead (and actually was)? Should I have just taken a flop?