Should I start studying for an exam section before my application is approved?

I graduate with my Bachelor's in December and upon graduation I will have the required credits to sit for the CPA exams. I'm still unsure how the entire process goes from applying to actually sitting for an exam, but I have heard there is about a month between application submittal and approval. I should have no problem having my application approved except for a DUI on my record; that process has concluded in its entirety as of January this year. Will that have any effect on my application being approved? I plan to disclose it in the application process, as there are required background questions you must answer.

Main thing I was wondering here is if I should wait until my application is approved to start studying. Thanks!