DL often cancels a flight for a while, then reinstates it later. I've had it happen where I got reticketed for a day earlier or later, but then the original date flight comes back and it's a hassle and rather difficult to get it back, due to only higher cost availability for it.

So here really it depends. If your travel date is flexible, proactively get it changed now for peace of mind. If you prefer to travel on the date as now ticket, then wait until some 3-4 months out and if it's still gone then, then call to reticket.