@Angela ********
you're not understanding the process.
Whether you start with the 90-day non-O or the 1-year non-OA, the process in Thailand is the same.
You'll be doing extensions every year from the immigration office. Each year you will apply for a 1-year extension based on retirement. There's no more non-O or non-OA once you're in Thailand, you're doing extensions.
The difference is that the non-O doesn't require insurance for extensions, but if you start with the non-OA, you'll be required to hold this mandatory insurance forever, as long as you continue doing extensions.