Mr. Tjinder first appeared during a flashback to 1957, where he was in a bike race. He put a cage around his bike due to his family's history of falling victim to tigers during bike races. Unfortunately for him, the tiger had a blowtorch, rendering the cage ineffective ("Tour de Ferb").
Since the flashback with Baljeet's father sporting a thick mustache takes place in 1957, he should be at least in his early 70's. ("Tour de Ferb").