First off
@Ma***
you're going to have to decide whether you're getting this "retirement visa" from the immigration office here in thailand after you arrive
OR
if you're going to get it from a thai consulate in your country BEFORE you wing your way here.
Once you have that decision hashed out then people can advise you what to do for that particular situation.
Just so you know getting the year-long, mulit-entry Non-Immigrant Type O-A (Long Stay) visa from a thai consulate in your country is definitely the way to go because it gives you almost 2 years of stay in thailand.