Can I figure out last year's aging with schedule c profit and loss form?

Your 2022 AGI is on line 11 of your 2022 Form 1040---your tax return.  If you filed a joint return that amount is the same for both spouses.

You have to access your own account and/or  print it for yourself using exactly the same account and user ID that you used when you prepared the return.

Start a 2023 return online and enter some personal information  so that the menu on the left opens up and lets you access your past year returns.

https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-access-my-prior-year-return/01/27010

Many people have multiple TT accounts and forget how to access them.  Log out of the account you are in now.

Account Recovery

https://ttlc.intuit.com/questions/1901535-forgot-your-turbotax-online-user-id-or-password

https://ttlc.intuit.com/questions/1901486-how-many-turbotax-accounts-do-i-have

Or did you use the desktop version of TurboTax?  If so, the files are on your own hard drive or any backup device you used like a flash drive.

No.

Looking at your Schedule C isn't a good way to find your last year's AGI.

Please follow the instructions in this TurboTax Help article on How to find your last year's AGI.