We have been on this situation, including the country club vibe, but didn't have the entry year concern. We were so undecided and worried the current school would think poorly of us if we applied out and either didn't get in or chose to stay there. We didn't want to disrupt our kid's schooling. In the end, we decided to apply in the winter and see how the school year progressed. By the time we were accepted in March, the school year had completely unraveled and we were so grateful to have applied and have the option to leave.
If the school you want to go to has precise entry years and is competitive in non-entry years, then perhaps consider waiting, but speak with admissions staff about that.