Have you reached full retirement age?
yes
you can choose to start receiving benefits before the month you apply .
What if I have not signed up?
n some circumstances your Medicare coverage may be delayed and cost more .
Is there additional information about early or late retirement?
read  Retirement Information for Medicare Beneficiaries
So if I don't sign up medicare coverage may be delayed?
yes n some circumstances your Medicare coverage may be delayed and cost more .
What's the best time to start retirement benefits?