The rules on St. Bart's should be the same as Saint Martin. That said, why procrastinate? My two cents ... You're going to do it sooner or later, so just get it behind you and be done with it. We had the same issue with Mrs. Alaskan's passport expiration date last year, so we just went ahead and renewed it. Without using any of the expedited services, we had her new passport in 3 weeks. Plus, she got a new, "custom" photo for the little blue book. Problem, what problem?
