first day/the first day

English as a Second Language English Vocabulary, Grammar and Idioms
1
  1. I broke my leg the first day out on the slopes.
  2. I broke my leg first day out on the slopes.
  3. I broke my leg out on the slopes the first day.
  4. I broke my leg on the slopes first day.
  5. First day itself I broke my leg on the slopes.
    Are all these sentences correct?
2

The first four are all possible.

“itself” in #5 seems odd.