Cashing in 3a

I am turning 60 on 3.5.2022 and retire on 3.5.27.

I have collected 5 pillar 3a pots as suggested and was going to cash one in per year. I had always assumed that I would start cashing them in from 66 years old onwards.

Now I understand that all of my 3a pots have to be cashed in on my 65th birthday so I have to start cashing them in from the age of 60 onwards.

So if that is correct, I can cash my first one in on  my 60th birthday on May 3?

You can begin withdrawing from your pillar 3a from age 60 (5 years before legal retirement age for men). If you keep working up till the age of 70, you can postpone withdrawal as far as that. Since you're retiring, that isn't the case.