Thanks for bringing your concern to our attention and for joining in on the thread, @jaslyncakes.

I'd be glad to assist you in changing the date of your inventory items in QuickBooks Online (QBO).

We can make some changes to the item by clicking Starting value option for you to be able to enter the correct date.

Note that doing this will affect the initial value of your inventory. Here's how to do it:
 

1. Click Sales on the left menu and go to the Products and Services tab.
2. Look for the inventory item and click Edit.
   
3. In the Product/Service information window, click the Starting value hyperlink.
   
4. Click Continue and it will route you to the Inventory Starting Value page.
5. Change the As-of date and other inventory details if necessary.
6. Click Save and close.
   

For more tips and guides while managing your inventory items, we can check this link: Manage your inventory, products, and services in QuickBooks.
 

Additionally, I've added these articles to learn more about the inventory feature in QuickBooks Online:

• Set up and track your inventory in QuickBooks Online
• Adjust Inventory Quantity On Hand In QuickBooks Online
• Edit An Inventory Quantity Adjustment

You can always get back to us if you need additional assistance with your inventory. Have a great day!