I've never switched schools, but I think you should probably expect something like the primary to high school transition, albeit to a lesser degree. From simple observations, all the new kids seem to more or less blend in fairly well.
If you got accepted into the same school I attend, there should be a camp very early on in the year (actually most schools have this, I think) where they encourage the grade to "bond" with each other (but it's really just an excuse for us to get to know the new kids and encourage friendships etc.) To a peer, the transition didn't look too difficult. Schools will also try and accommodate you/ ease you in in as best as possible and will provide a support network if you do have any issues.
Having said all that, you will be in a different environment, away from your usual friends and that may or may not be in your comfort zone. I would imagine to expect some feelings of loneliness or displacement for the first few days, but in general just be yourself and you'll be fine.
Congratulations for your acceptance