Remember that final, final chapter of Harry Potter and the Deathly Hollows book (and film, of course)?
It was a flash forward, nineteen years after Harry and his pals graduated from Hogwarts.
The chapter described what had happened since the famous wizards left school, including the fact that Harry married Ginny Weasley (cuties), and had three gorgeous kids together.
Lily Potter II, James Potter II and Albus Potter were Harry and Ginny's aptly-named children, who all went on to follow in their parent's footsteps.
This all brings us back to our story, and the fact that today is the day that Albus Potter starts in Hogwarts.
We have the INCREDIBLE J.K Rowling to thank, as she kindly reminded us all of this important anniversary.
Today's the day Albus Severus Potter boards the Hogwarts Express at King's Cross for the first time #19yearslater— J.K. Rowling (@jk_rowling) September 1, 2017
The author tweeted her followers this morning, marking little Albus's special day!
Naturally, Twitter erupted, which led to some really brilliant fan commentary, and some serious nostalgia:
You know what that means? Teddy and Victoire are snogging.— Every Orange Box (@everyorangebox) September 1, 2017
Wishing Albus the best first day, ninteen years later!