Not for the OP but for anyone who may need to complete the SF86, start gathering all addresses for places lived in the last 10 years. Names and addresses, phone numbers, for people you are closely related to. Addresses and names and dates for any employers you have worked for. Names and addresses of any schools attended.
Once you complete the paper copy, and you have done so perfectly and honestly, make a copy of it. Keep either a digital or paper version in a secure location. DS has a copy of his with him in a secure location and I have a copy in the safe here at home in case he were to ever need it.
If you stay in the service or obtain a job that requires a clearance, you will have to complete updates to your clearance. Any variation in your initial application would be noticed, so keeping an original will facilitate completing any additional applications/updates.