Reincarnated As The Villainess's Best Friend

My world ended in chaos, and I died trying to save it. I was Grand Mage Dreyfus Belford, the most powerful mage in the world — or so I thought, until I failed to stop an evil villainess from destroying it. Now, I’ve woken up. Fifteen years in the past. And somehow, I’m not me anymore. I’ve been reincarnated as Rin Stormborn, son of a high noble... Best friend to the girl who's destined to destroy everything. Armed with all my memories from my previous life, I’ve been given one last chance to change the future. All I have to do is survive magic school, navigate through dangerous noble politics, and keep my best friend from starting a world-ending apocalypse. Seems pretty easy. What could possibly go wrong?