Thank you Deborah!
They do share a cage
We also have what I was told to be a female cockatiel of the same age
She has her own cage
I feel there's a chance it's a male though lol
She flies and plays with her alot and will sometimes land on my head and preen my eyebrows if the cockatiel is with me.
So I have read the links you sent and had also read lots about egg laying
Thank you for the confirmation of her gender! The pet store employee felt she was at 5 months but couldn't confirm at the time.