Cyntoia Brown was convicted of murdering Johnny Allen two years ago when she was 16 years old.
She received an automatic life sentence, making her eligible for parole in 51 years.
But she was also convicted of aggravated robbery in the case, and the prosecution wants to tack on an additional 15 or 20 years to the end of her murder sentence.
Brown's lawyers think she should be able to serve both sentences at the same time, making her eligible for parole at 67 instead of 82.
Her victim's family doesn't think that's fair.
"Your honor I want her to get the maximum. I don't hate Cyntoia. I don't know Cyntonia, I just hate the act that she did," Joanne Allen, a relative of the victim, said.
The judge will make a decision on the sentence in the next 10 days.
