Tainted blood - a Severus Snape X teacher OC

introduction

Basically this is my new story, I haven't written much in years and I may be a little rusty but you know ... Snape.

Here's some basic info about my OC

Name: Aurora Black
Family: Sirius and Regulus ( brothers)
Bellatrix and Narcissa (cousins)
Nymphadora and Draco ( second cousins)
Age: 28
Past: followed her cousin and eldest brother following the dark lord, she bears the dark mark on her arm
Hair colour: Brown
Eye colour: Grey
House: Slytherin
Occupation: teacher at Hogwarts ( astronomy)