After you file

I owe for 2020 so it could be a long time before I get a bill from them. I do not want to pay interest. I added my sister who moved into my basement who is disabled and now as a dependent she wont get a stimulus. I would rather she did. She pays a little to me to help but not equal to what we could get for a renter. I do not know what to do. I can amend and remove her as a dependent but could it then be too late?