My first confirmed A*s were in English Language,English Literature and Core Science in Y10 you should probably give it to English Language since I was expecting that A* earlier from Easter,when all the coursework had been marked and the expected coursework marks added to give an A*.My first A* in a unit was in Unit 1 Maths(79/80) in Y9.
I've got no official A*'s yet, but my first was in Year 9, where I did an English GCSE paper and got something like 77/80. Then in the same year I also got an A* in a physics test for P1. This year, I've gotten an A* in B1 and also in C1, as well as in a music listening mock and a music performance.