Note, by grouping by date_part, you'll aggregating across years. If you use date_trunc, you'll retain the year information with the month. The prompt was a bit ambiguous, so this definitely counts!
This is absolutely a correct solution, just want to note that a more common definition would put the anchor point in the center, so that would make it 14 days preceding and 14 days following. This is a correct solution though, just a less common one.