As a general rule, unless you are applying this cycle, take the exam when you feel you are ready. I haven't taken the DAT yet, but with these standardized tests, they are rarely testing your intelligence. They are more about how much practice you have done (which increases familiarity with the material and makes you feel more "ready"). If you are in a hurry though for some reason you can take it now I guess.
I am going to assume you are either a 3rd or 4th year student in college. You can still apply next cycle for 2013 Fall if you take the DAT in June 2012 (and if you need to repeat it I think the colleges will accept scores until Nov or December).
EDIT: By the way my test is in two weeks as well (19th). I don't feel like it'll be a breeze or anything but I feel I have done a good amount of preparation for it...whether I am deluding myself of I have actually prepared well will be for ADA to cast judgement upon on the 19th.