I filled out & submitted my fafsa but I realized that my parents can use IRS.
I can’t access the IRS yet because it takes around 2-3 weeks and I don’t think my parents’ is ready yet.
So eventually I have to resubmit my FAFSA but my question is, Do I have to use the IRS? Is it beneficial since it’s accurate?
& if I resubmit my fafsa, do I not qualify for some grants that they give for the early apps?
It is good to use the IRS retrieval because you will know that the numbers are correct. However, it is not necessary unless the school tells you that you need to do it (for example, if you are selected for verification). If you refile, the initial date of filing is what schools will use for the date submitted.
Thank you so much!!! 
If this statement is in your fafsa SAR : “Your FAFSA has been selected for a review process called verification”, then you need to use IRS retrieval/