When should I report my 90-day registration after renewing my retirement visa in Thailand?

Your 90 day report is not reset with your EOS; only if the immigration give you a new date.

Report as usual

Seeing as you said you 'renewed' I'll go under the premise that you were on a yearly extension and you applied for another year extension in Jan

Getting a extension doesn't reset the 90 day reporting

UNLESS

when you got the year extension inked in they also gave you a brand new 90 day report receipt showing a new date 🙂

So if you don't have a new 90 day report slip in your passport your report is due March 12 like it was before you got the extension