Mi ekkomenciĝis antaŭ hieraŭ.
is it ok to but the jam before the mi?
Yes, but some consider it poor form. Duo might be one of them.
I just picked the right answer and it says it was wrong and this has happened to me many times before...... should I report it?
Certainly. If you ever believe that you are right and/or Duo isn't, then please report it. It's one of the best ways they have of knowing where problems are in the database.