te suguiero que uses esta función - DaysBetween(dtNow, dtBirth);
Código Delphi
[-] var dtNow, dtBirth : TDateTime;
DaysFromBirth : integer;
dtNow := Now;
dtBirth := EncodeDate(1973, 1, 29);
DaysFromBirth := DaysBetween(dtNow, dtBirth);
gertorresm
Colombia