Filter report - Custom Field Date - Report creation picking up "account created date instead"

I want to create a report that charts number of accounts that became customers by a custom date field in the Account Record.

My "custom date field" is MM/DD/YEAR -- I want to pull the "Number of Customer type Accounts" by "Current/Month"

When I create the report, include "# of Accounts" and "Calendar Month" it gives me a list by "created date" not "cusom date field"

Any suggestions -- and thank you.