The girl appeared at Bristol Crown Court on Monday (12 July) charged with murder. The Crown accepted her plea to manslaughter on the grounds of diminished responsibility.
As a result of expert medical opinion, it was accepted that at the time of the offence, the defendant was suffering from a significant abnormality of mind.
She was remanded for pre-sentencing reports and the case was adjourned for sentencing to a date yet to be set by the court.
Mr Hendricks, 24, sadly died in Russell Way, Crawley, after being found with a stab wound to the chest on 27 October last year.
Nimroy, who was known as Nim by family and friends, and the girl were known to each other.
Detective Chief Inspector Andy Wolstenholme from the Surrey and Sussex Major Crime Team said: “The death of Nimroy Hendricks is heart-breaking, and the whole circumstances of this case are both complex and tragic; our thoughts are with everyone affected by the loss of Nim.
“The acceptance of the plea for manslaughter was taken in light of all the available evidence from expert witnesses, and only after painstaking examination and discussion between Counsel, the CPS, the Police and Nim’s family.”