If I'm a woman, I should say रही instead of रहा right? I used that and my answer wasn't accepted
Yes. You can report if you see the sentence again.
Can anyone comment on the word position of आज? I notice it often comes early in sentences, but not sure I understand the rules about where to place it.
The usual place to put it would be between the subject and the verb.
However, आज मैं चल रहा हूँ is also right. That places more emphasis on आज