Past life partners, soulmates, twinflames and some karmics may be old souls since its not their first life.
Twinflames have an age gap and often their bithdays, resemble a meaninful mark like for example some twinflames have the same numbers order differently or their age backwards.
Other example is that in a lifetime we may experience many deaths, and rebirths & evolution of counciousnes some so technically we reach diferent dimensions as we expand our experience & consciousness.
Aside from the popular belief, not everyone has a twinflame, if that was the case the connection would not be rare and all the lack of information on this connection would not exist, therefore please do not fall for false advertisements selling you the idea of the 10 steps to find your twinflame or the program to find your twinflame, there are however other methods of finding out by evaluating your relationship and connections, tarot readings and astrologycal reports aside from the obvious physical, even though they are made from the same essence they are complete individuals, and not always are they involved romantically. They do however have an earth mission to fulfill. They dont always reincarnate on same life path, only in divine timing(age gaps or birthday numbers backwards or matching if reorder or by numerology life path) but its persue by chaos since all dark forces will not want them together. Most often there is a chaser and a runner dynamic prior to union. The runner is the more physical attached to material or physical plane and its afraid of the connection. Prior to meeting each other they would have profetic dreams, dejavus, wish fulfilling, coincidences and strange ocurances.( Some especulate this is orchastrated by outside forces but the true union is when both are commited and agree to it and only then.) After Union they might heal the aspects needed at the time for expansion and evolution and might take each others caracteristics or personality traits and skills to balance out when they are distant. Union will only happen if both surrender to the divine and recognize the blessing of their encounter. Only when they are vibrating in honesty and love putting indoctrination and earthly programming to the side; this type of relationship is the hardest. If ego is not balance and they do not take action to heal the past traumas and events up till today. The Chaser was the person who was more aware. After Union both will become ceirtain of more or new or highlighted senses and or abilities.