FETCH record not working

FETCH record not working

I have 2 forms. One is called PERSONS (fields Account, Name and Age) while the second is called DETAILS (With fields account(Lookup) and Age). I would like to fetch the age from the PERSONS form and have it displayed onto the DETAILS form. I have used the code below (on user input for field account). However, it is returning nothing. Please help. What could be wrong here?

records = person[Account == input.account];
Age=records.Age;