I'm in the same boat as you, and have already started light studying in case I need to retake on sept. 9th. I do think retaking in January would be too late to help you this cycle. I mean you wont get your scores until february, then you'd have to update, and I've read on here that it's not always easy to get these DO schools to be aware of retakes at any time, let alone that late in the cycle.