I never technically switched specialization, but I have to say, I had NO idea whatsoever what I was getting myself into, at all levels of university so far. Don't go in thinking you will know or need to know everything. Pick it up as you go and keep open-minded.
Just be ready to learn, be resourceful and strategic in getting information and help as needed. There are a LOT of resources at any university for that, so don't lose track of them. Profs, TAs academic counselors, writing centres and other such campus features should be pretty much your best friends when getting a sense of direction. Talk to them lots, get help when needed (I've been a TA and writing advisor for the past couple of years, and you can get a lot of "mileage" out of us as far as advice - a shame so few students actually come to approach us). And to have a good idea of what you want to do, you need to go out and DO.
I say that as someone who's spent the past 6 years of university (bachelor's and masters) and now looking forward to 5-6 more (PhD), and enjoyed each one of them. Always enough to learn
