Could be fun. There are some points to work out, but there always are.
I can see the Arcane University as being something similar to what is intended, if I am interpreting correctly (which I may only be partially), but that does limit it mostly to magic-oriented characters. Would make most sense to my own stock, actually, but that made it almost instantly relate to something like Harry Potter (which might turn a lot of people off of it).
There are no huge public high schools, most people are either apprentices or have small schoolhouses with as many as two dozen students.
Correction--there are no huge public schools
that we know. Technically, there is a lot of lore that is not built in to the games that could exist, but is not important enough to include (or that there is not time or memory budget to include). Though I find it illogical that there would be some giant academy at every city smart enough to have a wall, a place with a lot of culture (such as any capitol, and especially somewhere like the Imperial City) would be very likely to at least have some sort of archive, at which point you have scholars, possibly large schools, and so on. I guess "public" schools are unlikely, but private schools are, even if just to the rich.
Regardless, if it was executed well, I think that it could be fun. For the sake of RP, most people have a much wider margin of willing suspension of disbelief. Maybe throw in a few plot ideas, and it will be easier to consider.