How hard is the ATPL theory?

[wiggy]

You probably say the exams i sat in order to proceed to the first year of high school,is that right?

If by High School you mean (copied from wiki.):

Secondary Education - Ages: 16 ~ 18

Γενικό Λύκειο (3 years), Geniko Lykeio "General Lyceum"

Then that sounds correct.

I'll leave the specifics to someone more familiar with the current exams.