@Michelle1426You can't charge a guest more to stay with you once they have completed their booking. You can set you pricing for holiday weekends well in advance: I set my pricing a year or more in advance.
If you cancel, the dates will be blocked as a penalty by Airbnb.
Personally, I would treat this as a learning experience and move on. Most of us have been there at one time or another: we forget to set a minimum stay for certain dates, or forget to update pricing, but it's too late at this point.