Kyrie Irving is the starting pg for the 'East'/Lebron's team in the NBA All Star game.
That's pretty much 'superstar' level at age 26 in my opinion.
Our superstar hasn't yet reached his prime, and is playing without much help on the offensive end other than Al Horford.
In the 2017 playoffs he averaged 26 points, 5 assists, 1 steal, 3 rebounds and in the 2017 finals he averaged 29.4 points, 4 assists, 4.4 rebounds and 1 steal.
To me, those stats cement his place as a superstar in the NBA at 26 years old.