Seriously... enjoy this year and next year as MUCH as possible. When I was 18 and 19 those were the greatest years of my life. Once you hit 20, it all slowly starts to fall apart. The real world sets in...
If I could go back to any age it would be 19. Granted you can't buy booze yet, but it was that borderline age where you're still young enough to be crazy, yet ready to migrate out of your teenage years.