The main out-of-universe reason for the Jedi Master's seemingly rapid aging is that Obi-Wan is played by different actors in those films: Alec Guinness in A New Hope and Ewan McGregor in the prequel series and the Disney+ series.
In reality, in A New Hope Obi Wan was 57 and in Return of the Jedi Anakin was 45. We know that Obi Wan was always Anakin's master, so Obi Wan is older. It's possible that Obi Wan was originally supposed to be in his 70s when he died and Anakin in his 60s.
Anakin's birth took place in 41 BBY, establishing him as 16 years younger than Obi-Wan. At the moment of his discovery on Tatooine by Obi-Wan and Qui-Gon, Anakin was merely nine years old. By the time of “Attack of the Clones,” he had reached 19 years, and in “Revenge of the Sith,” he was 22.
Why Obi-Wan Wore Pieces of Clone Armor When Other Jedi Didn't - Star Wars Explained
How old was Anakin when he died?
Even though Luke tried his best to protect him, Anakin accepted his fate and expressed his love for his son and daughter, Leia, whom he learned about before dying. While it seemed like Anakin had lived a long life, his choices eventually led to his demise at 45.
Padmé was born in 46 BBY (Before the Battle of Yavin) and Anakin's miraculous Force-created birth came in 41 BBY, so Padmé was five years older than him. They did not meet until Star Wars: Episode I - The Phantom Menace, which took place in 32 BBY.
Darth Vader, the man that was Anakin Skywalker until his early twenties, is now a 32-year-old Sith Lord in his evil prime. By contrast, the once-optimistic Obi-Wan Kenobi is weaker: a 48-year-old former Jedi trying to part ways not only with his past but with The Force itself.
Back to childhood. That means Luke Skywalker will be 9 or 10 years old when the series begins. Obi-Wan, meanwhile, will be about 48 years old, just nine years after his death in A New Hope.
The main out-of-universe reason for the Jedi Master's seemingly rapid aging is that Obi-Wan is played by different actors in those films: Alec Guinness in A New Hope and Ewan McGregor in the prequel series and the Disney+ series.
Of course, the main reason Obi-Wan couldn't kill Vader in that moment was for the sake of the original trilogy canon. However, even if canon wasn't an issue, it still would've been out of character for Obi-Wan to kill Vader in that moment. Obi-Wan has never been one to take joy in enacting revenge.
The Obi-Wan Kenobi is next in the Star Wars timeline, taking place nine years exactly ten years after Obi-Wan left his former apprentice for dead on the lava fields of Mustafar. This means Darth Vader is 32 in Obi-Wan Kenobi (his master, in contrast, is 48).
The 1999 film Star Wars: Episode I - The Phantom Menace takes place in 32 BBY. In the film, a 25-year-old Obi-Wan meets a young Anakin Skywalker, subsequently becoming the boy's master when Qui-Gon dies at the hands of Darth Maul.
Of course, Padmé ultimately died in childbirth, meaning she was only 27 when she passed away and Anakin was just 22 when he was transformed into the mechanical monstrosity known to the galaxy as Darth Vader.
Yoda's age at death, a hasty 900 years old, reveals the absurd constancy of his species. This fantastic life span sheds ablaze on the mysteries of the Star Wars universe. His continued activity accustomed him to coach endless Jedi, including the allegorical Luke Skywalker.
Legend had it that Yoda—a Jedi who became Grand Master—was trained by N'Kata Del Gormo. A Force-sensitive Hysalrian, N'Kata Del Gormo was trained in the ways of the Force and achieved the rank of Master within the Jedi Order.
It was believed that Grogu would eventually become a victim of Kylo Ren's destruction of Luke's Jedi Order. However, The Book of Boba Fett revealed that Grogu chose to follow the Way of the Mandalorian rather than become a Jedi, sparing him from Kylo Ren's wrath.
So for every 10 years of Yoda's species would equate to 1 human year. So Grogu would be the equivalent of a 5 year old human and Yoda would equate to an elderly 90 human years.
Kylo develops a close relationship with Rey and starts feeling genuine affection towards her, so when Snoke reveals that he had manipulated their bond and tortures her in front of Ren, he looks furious at his master. Thus, when Snoke orders Ren to kill Rey, he chooses to save her and kill his master instead.
The term "Sith Lord" generally encompassed members of both sexes, although some female Sith such as Lumiya, Tahiri Veila, Olaris Rhea, and Vestara Khai were styled Sith Lady. Originally, "Sith Lord" referred to a high-ranking member of the Sith Order's society.
Finally, Rey is Kylo Ren's aunt through Anakin Skywalker. This means that Kylo and Rey's romance is just as genetically awkward as Luke and Leia's kiss on Hoth was. Granted, neither pair knew they were related at the time, but that's no excuse.
