Can I renew my retirement visa in Thailand immediately after 2 months of meeting the financial requirements?

Using the term renewal implies you are already on an extension of stay? If so the 90 days is irrelevant you can go for a new extension when your money has been in the bank for 2 months and you have less than 30 days left on your current extension

I am going to assume that you entered Thailand with a Non O Visa as a retiree that you obtained before your recent arrival date in Thailand.

Suggest you ask your local Thai Immigration office for their list of requirements for the one year extension of stay as retired in Thailand.

The 800,000 Thai baht required to be deposited from an international transfer into your Thai bank account, in your name only, MUST be in the bank a full 2 months before you make an application for the one year extension of stay as retired .

When you meet the 2 month seasoning and you have 30 days or less left on your current 90 day entry stamp (some offices are 45 days or less)