Sandra's class, Talisay, delivered a piece entitled "Ang Sabi ng Idol Ko". They've been practicing this piece for days and Sandra would sometimes come home late. That's Sandra in the middle, with the glasses.
That's not their school uniform though. Their school uniform's a bit more conservative and is shown here.
Their attire is a costume that's (Korean? Japanese?) Anime inspired. No wonder Sandra was all excited to wear their costume!