Castle Town in Miyapur for a class 8 joiner next June, if the family moves that side

My niece lives with her parents, but I'm very much part of her school life: a fair share of the runs and most of the science homework panic. Her parents are looking at flats around Miyapur for next year, and Castle Town has come up a few times. She would be joining in class 8. Does anyone know whether they take students into the middle classes, and whether there's a test for joiners? She's bright but a little anxious, so I'd like to know what to prepare her for rather than spring it on her ♥