It is never too soon to begin planning for your retirement.  Check out these benefits calculators: 

Thrift Savings Plan
Thrift Savings Plan Includes calculators for estimating the growth of your TSP account, and for estimating the monthly annuity payments your account balance would provide.

Social Security
Estimate your Social Security benefits.

FEGLI
Determine the face value of your life insurance, how much you are paying, and how selecting different options would affect your payment.  

Financial & Tax Planning