Kawaki in Boruto: Two Blue Vortex is operating as a dark mirror to the supposed character's journey. His complicated connection with the Uzumaki family and his woeful backstory have made him a fan favorite despite acting in a vicious role. The character's age advancement throughout the series reminisces about his growth from a broken child into a tough young adult with devastating power.
Throughout the series, Kawaki's age changes depending on the timeline being considered. In Boruto: Naruto Next Generations, he commences at 14 years old, which pushes him two years older than the 12-year-old protagonist. Following the three-year time skip in Boruto: Two Blue Vortex, Kawaki has grown to 17 years old, putting him almost an adult with fully developed fighting capabilities.
Kawaki makes his debut in the early episodes as a teenager, around 14 years of age. This age places him in the older bracket among the new generation of shinobi. His maturity level exceeds that of his peers due to his traumatic experiences under Jigen's control.

The two-year age gap between Kawaki and Boruto forms an enjoyable dynamic in their relationship. Despite being adopted into the same household, Kawaki functions more as an older brother figure. His experiences with the Karma mark and scientific ninja tools give him advantages that extend beyond mere chronological age.
Still, the exact chronology in the Boruto storyline isn't clearly defined and often leaves room for interpretation. The character's maturity level often oversteps that of adults in the series due to his unique cases. His experiences with loss, betrayal, and responsibility have aged him further than his chronological years.
Post-Time Skip Age in Boruto: Two Blue Vortex

In Boruto: Two Blue Vortex, Kawaki reappears as a noticeably more mature teen, now aged around 17. This three-year jump alters him from a teenager into a young adult on the threshold of full maturity. The time skip entitles the character to develop both physically and mentally, though his core incentives stay intact.
At 17, Kawaki possesses the combat experience and emotional intensity of someone far beyond his years. His dedication to protecting Naruto and Hinata has only strengthened during this period. Due to the influence of the Omnipotence ability, Kawaki is now widely recognized in Konoha as if he were Naruto's own child by blood.
The age advancement images the series' shift toward more mature hooks and higher stakes. Kawaki's increased age links with his enhanced abilities and his role as one of the antagonists in the current storyline.

His younger self displayed more vulnerability and uncertainty about his place in the world. The older version demonstrates unwavering conviction in his misguided mission. The three-year training period has refined Kawaki's combat skills considerably. His mastery over the Karma mark and various jutsu techniques has reached new heights.
His current age of 17 positions him perfectly for the climactic confrontations expected in future chapters. As a near-adult with fully developed powers, Kawaki represents a legitimate threat to established characters and the village's safety. The age factor also emphasizes the tragic nature of his character arc. Despite standing only 17, Kawaki has already undergone more loss and made more difficult decisions than most adults.
As such, Kawaki's character development in Boruto via these formative years showcases the impact of trauma, family bonds, and misguided loyalty on a young person's psyche. Even after all that, he is still continuing down his current path, or finding redemption. This or that, his age and experiences will undoubtedly shape the final chapters of his story within the series universe.