As a reminder, the Thesis Center deadlines for this term and summer term are posted at http://graduateschool.usc.edu/current-students/thesis-dissertation-submission/submission-deadlines/.
If you want your degree to confer this spring (May), you must have your dissertation defended and the checklist submission completed by noon on Friday, March 23 with your final manuscript uploaded by Friday, March 30 at noon. Times are PST.
If you want your degree to confer in the summer (August), you must have your dissertation defended and the checklist submission completed by noon on Friday, June 22 with your final manuscript uploaded by Friday, June 29 at noon. Times are PST.
This might be a good point to check in with your chair and develop a timeline for your defense, working backwards from these dates.