After you file

if you didn't keep a copy then you are out of luck. Neither Turbotax nor the IRS maintain tax returns going back that far.  However, the Social Security Adm would have copies of any W-2's (not a complete 1040) you received for that year. But there is a fee.

 

https://faq.ssa.gov/en-us/Topic/article/KA-02501