Can I renew my Non-O marriage visa two months before its expiration date?

One warning people,

You cannot mention using agencies or agents on this group.

Not at all, not in passing.

That's just how the group is set up.

Nope you cannot 😕

While you don't say where you are in thailand, (as in which of the 80+ offices you use) the soonest any office lets you apply for a new extension of stay would be 45 days before the current stamp expires. (Bangkok, Chiang Mai, Buriram, Phuket, Samut Prakan and a few others allow the 45 days before)

Most other offices allow you to do it when you have 30 days or less left on your current stamp