What will happen if I am younger than full retirement age and make more than the yearly earnings allowed.?
Your earnings may reduce your benefits if you are  at full retirement age.  Two months are added for every birth year until the full retirement age reaches 67 for people born in 1960 or later.
What year does full retirement age begin for age 66?
Full retirement age is 66 for people born between 1943 and 1954.  Begining with 1955, two months are added for every birth year until full retirement age reaches 67 for people born in 1960  or later.