Heads up on the river

[Guy McSucker]

I'm wondering what you guys would do in this situation against a generic unknown player.

I sit in a 50c-$1 NL game online with $100 and post a late position blind. Most stacks are between $70 and $130.

I get KJo. A few people call, I check, button calls, blinds check.

Flop comes K-J-8 rainbow.

SB leads $4 into a $6 pot. One player calls. I decide to test the waters and raise to $20. Button calls, other two fold.

Turn is a J. Only KK and JJ beat me now. No preflop raise means I am almost 100% sure I am ahead and almost can't be outdrawn.

I check. He checks behind. Should I have bet this?

River is a blank, not completing any of the straight draws on the flop. I have $79 left and my opponent has me covered. Pot is just over $50.

Your move?

Guy.