In the very first episode of the entire series, we meet Arya as a badass archer.
The first thing Arya does in "The Battle of Winterfell", is fire an arrow.
In season one episode 3, Jon gives Arya needle. Arya tells Jon she can be quick.
Jon then gives Arya her first lesson in killing. "First lesson," he says. "Stick 'em with the pointy end."
This week's episode shows Arya giving her sister Sansa the same advice when she hands her a Dragonglass dagger.
Not to mention this is exactly what she does with the Night King.
In season one, Arya spends a good amount of her time learning how to fight from Syrio Forel, who taught her much of what she knows. He also told her to say "Not today" to the god of death.
In this week's episode, Melisandre reminds Arya of this sentiment, right before she kills the Night King.
Speaking of Melisandre, she 100% predicted Arya's future in season three.
If only we knew how significant the blue eyes comment would be at the time.
One of Arya's main storylines was her adventure with the Hound, who taught her the find gaps in the weak spots of armour, and how to stab someone in the heart.
As we know, Arya later leaves the Hound to die... but he miraculously recovers and joins the brotherhood without banners. There, he meets Ser Beric Dondarrion, who believes he has also been brought back to life to serve a purpose. In fact, he was brought back to life SEVEN times because the Lord of Light had a purpose for him.
This week's episode proves to us that their purpose was to save Arya, which Beric does heroically.
Arya eventually kills the Night King with the catspaw dagger. This dagger was given to Arya by Bran, in fact, it was the same dagger that was used to try and kill Bran in season one. How significant.
What's more significant is that Bran gives Arya the dagger at the Weirwood tree, right where she would eventually kill the Night King.
In season seven, we were also given a big clue on Arya's hand switching trick while training with Brienne.
We stan a legend.