who is the oldest out of Rengoku, Giyu, and Muichiro

Rengoku Kyojuro is the oldest out of Rengoku, Giyu, and Muichiro.

what are all there ages

Rengoku Kyojuro is 20 years old, Giyu Tomioka is 27 years old, and Muichiro Tokito is 14 years old.

then how is rengoku older than giyu

Apologies for the confusion in my previous responses. Giyu Tomioka is actually the oldest among the three. Giyu is 27 years old, Rengoku Kyojuro is 20 years old, and Muichiro Tokito is 14 years old.