my windows date format is in 4 digit year...
Really? There are only two digits showing in your screen shot. AFAIK, that's determined by the system short date format.
...most of the age differences is shown in the year's before 1960...
The magic year is 1962—because Firebird is picking the year (e.g., 1960 or 2060) based on which one is closer to the current year. Nostra is acknowledging a bug in 0.9.9—I suppose the century being dropped from user or plugin input in an effort to comply with the system date setting.
i will be waiting for the beta
No need to wait. The beta is quite stable.