The teen became upset and told her: "Don't trash the house. It's not yours you stupid b****."
The girl confronted him and an argument broke out. It escalated to the point where the teen dragged her by her foot down the front step of the door on to the concrete porch.
He left her there, where she picked herself up unhurt while crying and moaning and went to her brother.
Brown approached the teen and an altercation broke out that started on the driveway and ended at the rear of the house when the teen pulled out a 12cm long knife concealed in a black belt bag.
The teen stabbed Brown so hard the knife handle snapped and the blade stayed lodged in his chest.
The teen then fled the property where Brown died a short while later despite the efforts of the party guests and emergency services.
When he was told by a friend Brown had died, the teen messaged back: "Bruh my intent was not to murder bro, ... s*** happens, life goes on, see you in the long run sweety."
He told police he thought "he was going to get a hiding so picked up the knife from the kitchen bench".
The teen said when Brown had grabbed him by the shoulders he had brought his hand holding the knife up towards Brown's chest which caused the inch-long fatal wound.
A three-week trial for murder was due to start yesterday but the teen admitted manslaughter instead.
He will be sentenced on November 3.
