I am turning 66 in Sept 2017, still working, if I begin taking SS benefits 9/1/17 at full retirement age, will I be penalized for the first part of the year that I worked.

Hi,

No. You can be paid starting with the month you turn full retirement age, regardless of how much you earn before or after that. You may want to consider running the maximization software available on this website before you file, though. You may have better filing options available to you.

Best, Jerry