First post-not sure if in right spot.

Flying with wife, and 10 year and 13 year old daughters to Aruba tomm morning out of JFK. Flight shows full. Problem is we have we have 4 separate seats, in separate rows, but near each other. Spoke to Delta-says there is nothing they can do right now-need to go to Delta rep at airport. Here are my questions.

1. Check in online today anway?
2. Go to Check in-counter to try to get new seats?
3. Go to gate to try and get new seats?

Thanks in advance for any help.