^Yes, it is.
However, there is nothing to fear. As you take a step up to the higher level, you will progressively adapt to that level if you consistenly try to keep abreast of everything around you.
The point of Year 11 is not necessarily to excel from the start. The whole point is to LEARN. At the beginning of Year 12, you will basically repeat everything you have done in Year 11. So, the point of Year 11 is to learn how the assessmenets are dealt, how to study, how to adapt to teachers/students, how to form study plan, how to motivate yourself and etc.
I failed my first term of Year 11 miserably. I was never ranked 1st in any of my subject at the beginning but I kept my workload higher from the following term and I did significantly better at the end.