A new quest will pop up once your first pet reaches level 3. It will send you to either Audrey Burnhep in Stormwind or Varzok in Orgrimmar. These trainers will offer a quest chain to battle specific Pet Tamer NPCs on each continent. Defeating each of these NPCs will reward a nice chunk of experience for your pets, as well a Sack of Pet Supplies (which has the chance to drop the Porcupette companion, among the always-useful pet bandages).
World of Warcraft (also known as WoW) players have highly requested the classic version of their favourite game. As with any game, changes and major updates are added over the years. Since August 2006, many changes to the game have not been received well: such as trivialising levelling up. The level cap will drop from 120 to 60, but contrary to how that sounds, it will be a far more grindy journey of fun and progress. The current developers have made levelling up very fast in comparison to the classic days, purely to focus on end-game content and raiding which many people do not enjoy. Prior to these changes, many people enjoyed the games for years whilst not hitting max level, something never seen in the modern edition of World of Warcraft. The levelling process was a journey, having fun with professions and the grind that is no longer found. Of course, there are countless other changes that will be reverted, as you might expect when comparing something from 2006 to 2019.