Be aware that there are two levels of linking. Just requesting that the reservations be linked, you will be fully linked meaning you can make reservations for shore excursions, adult dining, spa, etc. and see their schedule (they can see yours as well). Even if you don't mind all of that, only one can be in their reservation online at a time -- if you've already booked your shore excursions, etc. that might not be a problem. If you just want to have dinner together, request that the reservation be "linked for dining only". They don't do seating for the cruise until a week or two beforehand so you still have plenty of time to link the reservations.