Calculated Column that only pulls data for Current year

I am trying to create a calculated column that Counts the age of a customer in Days IF the time the customer was created was THIS YEAR.

I've come up with multiple IF statements but nothing has worked properly. 

This is part of what I've got:

To calculate the age (in days) - AGE=DATEDIFF(Customer[CustomerTimeCreated],TODAY(), DAY).

What I need to do is create an IF statement:

AGE OF CURRENT YEAR CUSTOMERS = IF(YEAR(Customer[CustomerTimeCreated])= "Current Year", DATEDIFF(Customer[CustomerTimeCreated],TODAY(), DAY), "Previous Year Customer")

Any ideas on the best way to do this?