Thanks for joining us here on the Community, soszkamo-yahoo-c :waving_hand:
You can backdate your QuickBooks as far as you need, the simplest way to do this is to connect your bank account - if your bank is available on Open Banking, you can sync up to two years of transactions when connecting this.
Alternatively, you can download CSV statements from your online bank and import these into QB by going to the Cogwheel > Import Data > Bank Data.
Get back to us below if you have any questions on this!