Ok so I hid the extra fields, but what you said to do, doesn't help. I understand you're saying to pull the data from the DB, but I'm lost still.
Edit:
I was looking through the DBs and I see that xcart_extra_field_values contains the data as follows:
productid fieldid value
1 1 8
1 2 17
1 3 1970
I found a better script as well.
http://www.hscripts.com/scripts/JavaScript/age-calculator.php