User blog comment:WhiteArmor/7/7/777/@comment-95.154.11.60-20140119123901/@comment-7418318-20140119133548

"All the Dragon Slayers are more than 80 years old, that is at least a fact" Those are the actual facts, provided by Hiro Mashima himself. Everything else is just speculation and educated guesses.
 * Wendy is 12, Laxus 23, Sting and Rogue are 19.
 * Dragon Slayers were first created by the pro-Human Dragons to fight against the anti-Human Dragons, but later turned on their allies and began killing all Dragons, no matter which faction they belonged to.