Hello @jwilliams,
It's nice to have you in the Community. I can help you with fixing the beginning balance.
A correct beginning balance is important for a reconcile in order to ensure that everything will match up. I'm including an article that will guide you through correcting the beginning balance: My Reconcile Opening Balance Is Wrong. How Do I Make It Match My Statement?.
Additionally, I recommend the following link as it's a hub of articles to assist a user with the reconcile process: QuickBooks Online Reconcile Hub.
I'm confident that these links will get you on the right track and have the account reconciled like a pro in no time.
Please let me know if you need additional assistance. Wishing you all the best.