Will you be travelling with it a lot? 15.6" screened machines seem to be cheaper here in NZ than 14" but they're bigger to shlep around.
If you will be studying, you're probably going to be writing a lot, so keyboard could be important. But if the machine will spend all its time sitting on a desk, a separate keyboard will be cheaper and more satisfactory than choosing the laptop with the best keyboard.
I think it possible that a Chromebook wouldn't really be a good choice for Office.
My sense is that laptop specs haven't changed in ways that matter to the average user for years, except that a solid-state hard disk really makes a difference.
For what it's worth, the biggest tech dealer here regularly has off-lease Thinkpads and Dell Latitudes at very good prices. I've had good luck with a couple of Lenovo Thinkpads, and I got a Latitude from a different source which is also nice, and well up to non-gaming needs despite being a couple of years old (choose the machines that weren't used much). May not be right for you, but worth thinking about if your machine is going to travel a lot.