hello, Im a student in serbia. I started the first grade of secondary school this year and im planning to move to england at 17, in the third grade. here we dont have any exams that we take during the high school except for the one at the end of the 4th grade-at 19,which i wont be taking.i'm planning to take chemistry, math and biology for my A levels,so what are the alternatives for GCSEs, will i have to do them first in order to do A levels? Also, will i be year 12 or 13?