Yes on all counts.
And you correctly showed why adding the wordCount fixes any problems with going backwards. It causes you to "wrap around" from 0 to the last element. It's not needed when going forward, of course, but it doesn't hurt at all. So by having it there the code works for both directions.
An optimist sees the glass as half full.
A pessimist sees the glass as half empty.
A realist drinks it no matter how much there is.