Did you want it to start before 08/01/2021 ? Your 70th birthday?
Four months before the retirement date (70th birthday max) is usually the time period when you should actually apply - sounds like you didn't complete the application and plus there are those documents which they may require to process it. Think you will be fine since you aren't there yet but double check with them.
Here is some info that may also help you -
Set up, if you haven't already done so, your SSA.gov - "My Social Security account" - you can see if anything has been processed at all. - well maybe shortly since it just went through to them.
Four months before you want to start your benefits, make sure your application is complete, including any docs they need and you get a verification letter - (online in your My Social Security acct and probably in the mail too).
Read these pages and these topics:
SSA.gov - Retirement Benefits: Delayed Retirement Credits
Social Security.gov - Retirement Benefits

It's Always Something . . . . Roseanna Roseannadanna