Today, we're going to tackle the subject of worgen druids, whose lore is an even bigger rat's nest than the contentious subject we discussed last week. As a note on that, I feel obligated to stick to the official line, which is that night elves were the first druids. Read Xarantaur's flavor text again. Not only does he skirt the issue, but his own story is an oblique confirmation that he probably wasn't among the first druids if the Warcraft RPG's information on racial lifespans is still canon.
Malfurion Stormrage is a young adult by the War of the Ancients. Xarantaur references the War, the Sundering, and a lengthy period spent traveling Kalimdor in search of stories. He was about to die when he was gifted with immortality by Nozdormu, so it's probable that he, too, was a young adult when the War began. By night elf reckoning, a "young adult" (even before the immortality granted by the World Tree) is between 100 and 300 years old; a tauren with a vastly shorter natural lifespan would be between 30 and 50. Even allowing for the smallest natural age gap, Malfurion predates Xarantaur by at least 50 years, and probably a lot more, given that he and a host of other night elf druids enter Ysera's service in the Emerald Dream after the Sundering. While it's likely that the tauren weren't taught druidism long after the night elves, Blizzard's official line is that night elves were the first druids. They may retcon this in the future or at the very least clarify (and I hope they do), but Xarantaur's existence doesn't conflict with the idea of night elves being first.
The full series is available here: