Tableau Ticket Age Calculation

I need a Tableau calculation to count tickets open for a specific number of days within a month window. This should be based on historical data using a creation date field.

Requirements:
- Implement logic for a month window
- Handle historical data without a log date
- Use parameters for:
- Number of months in the past
- Number of days for ticket age

Ideal Skills:
- Proficient in Tableau Desktop
- Strong experience with date calculations and parameters in Tableau
- Ability to work with historical data