Achieving enlightenment is not the same thing as discovering your twin flame. Meeting your twin flame may cause you to examine the spiritual aspects of life and can then take you both on that journey. But, in general, enlightenment is out of the equation. Bonnie and Clyde were twin souls and they went on a robbing and killing spree that caused a lot of distress. So enlightenment and twin flames don’t necessarily go together.
Most people on this planet right now are not enlightened. They do not look within and see their connection with the Universe or with their Eternal Souls. So wherever they are on the path, their twin soul will be exactly where they are too. The purpose of meeting our twin flames is deeply spiritual. When you feel the wonder of it, that can catapult you into understanding the unseen mysteries of life.
Maybe you are an old soul, who has incarnated many times. Your twin flame will be on exactly the same level. Even if you live in New Jersey and your twin flame is in Australia, you really are the same soul. So it isn’t possible for one of you to be enlightened and the other one not. Both of you are One, and enlightenment has nothing to do with it. But be sure that meeting your twin flame always shakes you to your roots.