Continue along the path until you come to the platform with the switch/save point. The save point here has an extra option: "Teleport", which will bring you back to the entrance of Memoria. This is the last chance to leave before the end begins. Be aware that once you leave, you must come all the way back through Memoria again.

If you go forward, you'll meet Kuja. The first boss you must defeat is Deathguise, then Trance Kuja. After that, you'll take on the final boss, Necron. Good luck and enjoy the ending!