Worldwide.

Apology for my ignorance for not knowing the *.ac.uk for students in UK. I've did a slight modification to the form.

Universities in Germany and probably many other countries don’t have special e-mail addresses. I guess you will either have to verify manually (if there is indeed some kind of college or university behind the address) or just not accept those submissions.

Guess I will verify manually (I could always google).

That would help. Many German universities have rudimentary English versions, which makes things easier, too. I suppose it's enough to search the university's name and "email", though. I found some email adresses of my university that way, anyway. Thanks for doing this - I (and the other students, I bet) appreciate it a lot.

My school (yes I am in High School) doesn't have a .edu address, so entered my personal one. Acceptable?

Yes.