Good day,

I am trying to create a formula field in Zoho Desk to calculate an age, but I'm having trouble figuring out how to make the formula.

This is a formula I found, but it keeps telling me the wrong field name. Can someone please help me? 

Field name: cf_purchase_date

Year(Now())-Year(${cf_purchase_date})-If(Month(Now())*100+Dayofmonth(Now())>=Month(${cf_purchase_date})*100+Dayofmonth(${cf_purchase_date}),0,1)