Emmie, ash seems fine, but neither of the 3-letter possibilities starts with a letter common enough to be likely to be A. (That’s not to say the setter isn’t playing games, but A is usually one of the most frequent letters.)
Well done, emmie. I'm sure it is 'ash', despite the shortage of the letter A. The puzzle seems to be working out without any impossible words, so you get the gong.
I expect mouseymick will give more details later on.