Submit your AADSAS materials as early as possible. If you wait until you take the DAT, schools won't get your info until late August or September. If you submit everything in may, then AADSAS can verify all your GPA's, mail out your info to the schoolsand then they will just be waiting for your DAT's. If you're going to study all summer for the DAT, then do well. If you prepare, you will do fine. If you wait on everything and something happens (professor procrastinates on LOR, AADSAS loses a transcript, etc.) you might do great, but still not get in. If you're scores are good you can submit in July and get in, but it might be a whole lot more stressful.