@Martin **********
, What visa or extension are you now? Are you on visa exempt or tourist visa stamp?
In other words, What are you really want to do? Applying for an in-country initial Non-O visa based on retirement or applying for a 1-year extension based on being over 50 while you are already Non-O retirement visa?
Why I'm asking this is an in-country visa and 1-year extension are different.