Indian ring neck

Indian ring neck was told she is a female won't know till she's older.
She's about 8 to 9 months old, when she wants to be nice she gives kisses and will listen, loves toys, rehoming due to her aggressiveness twords my other ring neck.
And she bites kinda hard.
I believe she is jealous of my other bird.
Paid over 900 asking 600 she was bought from a store and is turquoise color.