Correct way to play quads?

[The_Good_Dr]

3-6 Live at a casino that I go to a lot. I have played with the button many times before. She is an elderly lady that always sits in the five seat. Not a very creative player, but plays pretty solid. I'm in the 3 seat when this hand gets dealt.

Folded to me two off the button. I get Q [img]/images/graemlins/club.gif[/img] Q [img]/images/graemlins/spade.gif[/img] and raise. Old lady in the 5 with the button calls. BB calls. Flop comes K [img]/images/graemlins/heart.gif[/img] Q [img]/images/graemlins/heart.gif[/img]Q [img]/images/graemlins/diamond.gif[/img]. I flop quads and am going to slowplay the flop. Correct?
BB check, I check, B bets. BB folds, I call.
From here, I put her on either a K, a medium pocket pair, or a big heart draw.
Turn is 8 [img]/images/graemlins/diamond.gif[/img]. I check, B bets, I raise, B calls. I raise because she isn't one to fold the turn. If she has any of the hands that I put her on, she won't drop. She plays pairs and draws to the river.
River is 4 [img]/images/graemlins/heart.gif[/img]. I bet out hoping she made her Ace high flush and she'll raise. It's very unlikely for her to bet a K or pocket pair after my c/r on the turn. She calls the river and turns over 10 [img]/images/graemlins/heart.gif[/img] J [img]/images/graemlins/heart.gif[/img]. She flopped an open-ended straight flush draw. That was the closet I've been to a jackpot. Anyways, was my play correct throughout the hand?