dependents over the age of 16 are not eligible for stimulus rebates, so she should not receive it,
if she is really not your dependent (you didn't describe whether she is in school, living you with, her income, etc) suggest amending 2019; that will set her up to receive the stimulus. Why did you list her as a dependent?
She can be a dependent on your return and file her own return - that occurs with high school students and college students all the time
