I had my first solo IFR flight today (I just obtained the rating) and I had a question about my flight. I flew the ILS 36 approach into Ocala which includes a VOR arc. I was assigned an alt of 3000 and told to report "when established" on the arc. The approach plate assigned alt for the arc is 2000. I maintained my alt until told my ATC to descend to 2000 but could I have descended sooner after I was "established" on the arc. What exactly does "report when established" mean? Does it simply refer to the course or the alt as well?