Let me help you enter the correct information in your tax profile settings, Carol Spindler.
QuickBooks will tax the allowance if it exceeds the 12,500 amount. Since you already have an income and are employed, there are some slight changes that you'll have to consider.
You'll also want to reach out to your accountant to ensure that your taxes are correct. You might want to check this article for more information: QuickBooks Self-Employed UK Tax Profile Set Up.
For reference, here's an article handy to know more about QuickBooks Self-Employed: QuickBooks Self-Employed Overview.
Let me know if you have any other concerns about your tax setup. I'll always be right here to help you anytime.