To the OP,
I am 17 years of age and I just took your quiz. When I got to the Demographics section, it said the since I was 17 or under, I needed to not proceed with your survey, but I could fill out the remaining questions on the page, so I did, and then when I clicked next, it said I was done. I had filled out most of the survey and didn't want the to go to waste. I wasn't sure if that's what you wanted or not. Sorry if this skews your results.
If this is NOT what you wanted, and the anyone under the age of 18 shouldn't take the survey, I think that you should state that BEFORE the quiz is taken.
Again, sorry if my confusion has skewed your results.