Hello, Ria -
Only the manufacturer of the Onga 443 MAY be able to tell you how old your pump is. You would have to provide the serial number for the pump, in hopes the company has manufacturing records in its archives. The company archives should probably have photographs of the Onga 443.
I refer you to Pentair, the oompany which owns the Onga brand name and manufactures the pumps. See the Pentair Contact Us page to find the email address for Customer Service:
The email addresses there seem to be for sales. I would still use the email address for the country where you reside and ask that your message be forwarded to Customer Service.