@Charmaine9 You didn't say what type of phone, and I only know the app on the iPhone). If you're using the iPhone app, go to your Calendar, then click the gear-like icon at upper right. Under that you'll find the Min/Max setting. (For others: If you're using a browser, also start at your Calendar. Near the upper right, click on Availability Settings. The Min/Max values are controlled from there.)
Note that in addition to your default Min, you can also set varying mins for specific date ranges. (If you do that, don't forget that you've done it, or else you might get confused later on when guests try to book but can't.)