I have been charting since october and i, as you know still havent had af, its better to start on the first day of bleeding - so ive heard but for us girls it may take a long time for af to start again, i suggest you start now anyway (the only reason i got my appt with the specialist is because i was charting and the doctor could not see a thermal shift)
I recommend it, even if depo hasnt come right out of our systems it good practice.
Have you got TCOYF, that will really help also i got the temp chart in a walet with a basal body thermometer from Boots, it was £14 but well woth the money, it sits by my bedside untill 6am when on goes the thermometer, it really was worth the £'s
Good luck