Every single human being possesses kundalini spirit in the base of spine from birth. When it activates entirely depends on us. Lord Krishna activated his kundalini fully when very young may be about four years of age. Lord Krishna was destined to become an avatar of his era from previous birth. His kundalini had to awaken fully early by default and so it did.
As ordained by god every human on mother earth can indulge in path of spirituality to awaken ones kundalini fully. Indulging in precepts of spirituality detailed in Bhagavad Gita and Upanishads (independent spiritual treatises) is a sure shot method of full kundalini awakening in present life time. Right from stage of Mahavira to Gautama Buddha, even Jesus Christ and Prophet Mohammed all indulged in kundalini awakening guided by precepts of spirituality contained in teachings of Lord Krishna.
If followers of Jainism say Mahavira had nothing to do with Bhagavad Gita or Lord Krishna, this is an absolute misnomer. Precepts of spirituality could be indulged by anyone, were never proprietary of any particular religion faith or belief. As Lord Krishna advent about thousand years earlier to Mahavira it is not hearsay but an absolute fact of life that Mahavira definitely indulged in teachings of Lord Krishna in Bhagavad Gita. The 22nd Tirthankara of Jainism Neminatha was a cousin of Lord Krishna and also a good friend.
Born in a Jain family, from six years of age I pursued teachings of Lord Krishna more than what was available in Jaina scriptures. Whenever I had a query and asked elders in the family and outside I never got any answers. When I indulged in 700 shlokas verses contained in Bhagavad Gita, I got answers to all my queries. Precepts of spirituality contained in Bhagavad Gita were crystal clear from the very beginning but to understand them our indulgence in contemplation (chintan) is necessitated.
In present times even a laborer or a cobbler could indulge in teachings of Lord Krishna in Bhagavad Gita to reach stage of enlightenment. When we indulged in self enquiry, Neti (not this, not this) it activated our kundalini in stages. As queries within us dissolved gradually, we became wiser in the spiritual journey of life elevating self to states of higher consciousness. As our kundalini neared Ajna chakra we were very near to reaching state of enlightenment.
If we can develop the capability of indulging in contemplation (chintan), we can cross ocean of Samsara (worldly life) by awakening our kundalini shakti in stages. Even as a commoner, one from masses we can easily do it and become an enlightened one provided we had willpower possessed by Swami Vivekananda. Field of spirituality does not relate to earthly wisdom, bookish knowledge as everything spiritual always comes from within.