It sounds as though you're a bit worried about taking the MCATs in August. I was a bit worried about that one too. I heard all of the rumors say that if you take the MCAT in August, then you will end up applying late and all the seats will be taken. Now that I have gone that route, I can say, it's somewhat true but not really. First, I don't think most schools will be filled by the time November or even December rolls around. So relax. Try to get everything in as fast as possible.
As far as being competitive. Aim for a 27 or above on the MCATs if applying to DO school. As far as science GPA goes, at least above a 3.5 or so for DO school. Of course there are always the exceptions. Be glad in knowing that DO schools do a much better job at looking at the exceptions than MD schools do. Be sure your recs are good and you've done a lot of extra activities. I think that for the most part, this is what is takes to be competitive. If you don't have all of the above don't worry. Like I said, there are many exceptions contrary to my point of view. Hope this helps.