I know you didn't enjoy university much, but why not sign up for an Introduction to Policing course at a local community college? Just take the one course to see how you feel, then sign up for more if you like it. (I got my associates in Law Enforcement from a community college).
Also, check to see if a local city/town has a Community Police Academy you can sign up for to make local contacts, learn some more about it, and have some volunteer work (graduates are usually encouraged to volunteer at stuff life local fairs/events with the force) on your resume.
You can also look for jobs in security while you're waiting. I know Securitas is a worldwide company. I worked for the US company for a few years and it was pretty decent (for a security company, right in the heart of the Recession that is

). See if they have a branch near you or if theres another security company, now is the time to apply since security officers are needed to protect retail sites during the holidays. While its not the most glamorous job, it pays better than working a register, its a step in the right direction, and you can usually get swell gigs that are perfect if you go to school as well.
Also, in the US, many police departments won't hire anyone until they're 21 or over (I know you're below that), so you have a few years to get some education, in shape, and spruce up your resume, as well as start your transition.