Your social security statement should be checked once a year, every year. 

If you have never logged in to your my SSA account, link to this instruction sheet .

If you have already set up your my SSA account online, log on to this link. It will start a two-step verification process. Step one: enter your username, password, and email on this page. Step two: a code will be quickly emailed to you; copy the code. Go back to the web page and paste or enter the code. After accepting their terms & conditions you will go to your my SSA page.