you should definetly apply right now. you have about two days left for most of the schools deadline is Dec 2. but NYU takes applications until feb 2 so go for it!!! I wish i had those scores.. just fill out ADA application before midnigh dec 2. basically pay fee, all ur info and have rec letters come after- with those scores schools will wait for you good luck
If it were me I would not retake it. You have a decent gpa and a good dat score. I would look at the schools you want to apply to adn see where you're at for next cycle. I dont think you should apply this cycle because of how late it is. You can instead spend the year improving EC's and getting a 4.0 over the next year to help raise that GPA. Then apply June 1st with a great app.
Do you really think you can improve much on that 21?
Don't retake. Your stats are fine (unless your sGPA is far below par). I'd be surprised if you didn't get any interviews past December. If for some reason you don't, prepare your application early next year and you'd be sure to get in.
Unless you're positive you can get a higher DAT, I'd side with the majority and say that your best bet this year is to sign up for some upper division science classes and ace them to improve your gpa a bit and strengthen your app. Unless you KNOW you can do better, retaking the DAT can be a large risk. What happens if you do worse? And a retake is pretty much useless if you do the same.
None of us here can really tell you anything, because we don't know you or your intelligence or your work habits or how much you studied to get that DAT score or how much better you can do. By all means, if you're convinced you can do better and you think it'll strengthen your application, retake the DAT, but honestly you have pretty solid scores from what you've said, so that's a decision no one but you can make. It's up to how well you know yourself at this point.