You were born on a Sunday. Be sure to type all four digits of the year. If you don't, you'll get the calendar for 62 A.D.-almost 2000 years ago!
To get a calendar for the current month, just type cal (no arguments). You can also get the whole calendar for any year by giving a single argument: the year you want (use all four digits for any year in the last millennium).
There seems to be a bug in September 1752:
But there isn't really a bug.
That's when Great Britain and the (then) American colonies adopted the
Gregorian calendar; what would have been September 3 became September 14,
and the beginning of the year changed from March 25 to January 1.
Bugs - in UNIX?