So Danny was introduced in 'Into the Dalek' S08E02 - Well as i was saying, He was introduced and Clara was introduced to Danny by the Head Teacher...

By the time The Caretaker was broadcasted, it's only been a couple of months via Clara's timeline with seeing Danny.

During the Caretaker, as soon as Chloe's parents sat down with Mr Pink; Mr Pink described Chloe as a disruptive influence. Whereas the teachers replied "Oh that's even better! Because 'LAST YEAR' YOU Said she was an even bigger disruptive influence, so it's an improvement." Mr Pink nods in agreement

Okay what's wrong with that line? Danny has only known clara for a few months, and by all means, Danny only started working there a weeks after Deep Breath... Have we missed a full year of Danny and Clara?

It might be "you" as in the school "you" rather than Danny personally, because he had to be told who they were.

As AdelaideGirl has pointed out, people use 'you' to mean 'your organisation' all the time. And Mr Pink would have a record of previous discussions.

No hiccup here...

'Last year' could simply mean before the turn of the previous year. In January you could refer to something that happened in December just a month back as being 'last year' and that would still be correct.

Thanks for clearing that up i suppose haha