How old is Gus from Tracy beaker returns?

Tracy is 22

Mike is about 50

Gina is about 45

Tee is 11

Carmen is 12

Lily is 12

Sapphire is 16

Johnny is 13

Liam is 15

Frank is 15

Tyler is 12

Rick is 14

Harry is 8

Gus is 13

Cam is 40

Seth is 22

Elektra is 15

Toby is 13

Jody is 11

Kitty is 12