I'm Under 21 But I Frequent A Casino That Is Strictly Over 21

Not exactly sure what the flair should be here. Basically, I'm in Washington State and I frequent a casino that is strictly over 21 (I'm 17). It's plastered everywhere and they site RCW 66.44.310. I'm not gambling or consuming alcohol, I just go there to eat at the restaurant (which also states you cannot dine there if under 21). I tried reading up on it but I'm not that good at understanding all this legal stuff. What kind of trouble can I get into if I get caught? My parents say it's fine but could this be really serious? Thanks in advance, I appreciate the help.

EDIT: Perhaps this was not clear but I am NOT gambling in the casino. Just eating there. And secondly, the restaurant is not a bar (in case that was a misconception). Last thing, I go with my family and I have no say in whether I go in or not (they think it's fine and no one cares). I am quite uncomfortable going in and am always paranoid.