@Mark *******
“FOR MY FIRST 90 DAY Visa Extension Check-in”
What a terrible terminology.
“visa extension check in” ???
You can’t extend a visa. You can only get a stay permit extended. The 90-days Non-Imm-O visa you entered with became invalid when you entered Thailand. It can’t get “extended”
WHAT do you want to know?
***Do you want to know from how many days before your 90-days stay permit expires, you can apply for the 1-year Extension of the Stay Permit?
ANSWER: you can apply for the one-year extension as soon as 30 days are left on your 90-days stay permit. On some Immigrations you can apply 45 days before
*** or do you want to know how to do the 90-days report on Immigration?
ANSWER: you must do your first 90-days report in person. You can do it up from 14 days before due date until 7 days after due date