Hey bro, I graduated from Ruse around a week ago.
Congrats on getting in - these next few years will be a hell of a ride.
Will say that high school isn't easy wherever you are, and it's only harder at Ruse. Very significant proportion of us spend time at tutoring, expect to be academically challenged for sure. You'll learn to be more disciplined and the academic environment at Ruse will only be more of a motivator. Don't worry about catching up - some of my best mates were transfers and given the selection process, I know you'll do excellent. It'll be challenging and everyone around you will be high achieving, but eventually you'll find meaning in your work and grow as a person, as a result.
One of the most important things you can do, though, is to find things you genuinely enjoy, both inside and outside of the classroom. Ruse has an underrated volume of extracurricular opportunities that you should definitely take advantage of. Much better to do well in them than otherwise. If you're hard-working and doing the stuff you enjoy, you'll be set.
Randomly checking BoS and thinking about doing BoS trials at 12am might be a factor in my sending of a slightly sub-standard response, so feel free to shoot me a message if I can be of any extra assistance.
YZ