Married in 2012
from 2012 to 2018 - tax filing status single
Spouse and kid came to usa - only in dec 2019 and they got ssn in 2020. They are gc holder in 2019.
About to file tax return for 2019 (married jointly) and would like to amend last 3 years tax return (2016,2017,2018) from single to married filing jointly.

My Tax Accountant is saying it is not sure if the amendment will be accepted.
What is the chances of tax amendment to be accepted?

If the amendment is not accepted it simply means I donated 10's of thousands of dollars