The tauren race is one of the more interesting prospects for roleplay, even if they might not seem like it at first glance. In the last ten years or so of Azeroth's history, the tauren have arguably seen more turmoil than any other race on Azeroth. They haven't just witnessed wars and conflict, they've uprooted their entire way of life from the ground up and watched it shift and buckle around them -- for both good and bad.
Goblins were first introduced as a playable race in Cataclysm alongside the worgen of the Alliance. And while the worgen, and Gilneas, have a rich history that goes all the way back to Strom and the founding of the first seven human kingdoms, goblins don't really have that kind of background. In fact, even though the goblins have been around as a race dating all the way back to the RTS games, they've never really been more than sidekicks at best, supporting characters and comic relief.
Dwarves and gnomes are fairly similar in background origins, which is why we're tackling both races here in terms of age in roleplay.
The pandaren race was introduced in Mists of Pandaria -- so what exactly do we know about their age and lifespan? Not much at all, really, which leaves the process of making a pandaren character a pretty big open book as far as determining the correct age is concerned. Then, too, is the history of the pandaren race, which has also been left much like a few other Azerothian races with a few key, defined events, and then a lot of nothing in between.