Are they on the internet at Hogwarts Academy? Do they even have computer classes? Do they use I-phones and tablets?

no, electrical devices do not work in magical places! so no they are not, but they don't need to be!

it was also set before everyone had mobiles (in the early 90's)

We have five kids (9, 8, 6, 5, 1). I don't think technology is bad, but it should be limited. Yes, it's here to stay but young kids are still developing all sorts of pathways in their brains that interaction with physical things enhances and technology does not help develop as well. So it should be limited to some degree. I think that what you are already doing sounds fine. You give her access but you don't let her do it all the time and you have her play with other things too. Just because technology is a big part of life, doesn't mean that it's the best part of brain development for a young child. Our kids have access to the Wii, the computer and the Kindle, but they spend much more time playing with actual toys instead of virtual ones.

HARRY POTTER