Laura Kinney also known as X-23 is the Wolverine female clone in the Logan movie. She is played by Dafne Keen, an eleven years old actress.
So this guide is preferably for a little girl's costume, otherwise you might get looked strangely...
Check out our complete guide to dress like X-23 in the Logan movie:
Complete X-23 Costume Guide
The tshirt that Dafne Keens wears in Logan for her Laura Kinney/X23 role is actually a tshirt-dress, it is grey with a rainbow and a unicorn.
The t-shirt is unidentified but a replica has been made.
The backpack that Dafne Keen uses in Logan for her X23 (Laura Kinney) role is a green rucksack with a simple closing straps and 2 leather lash points on each side (to which she has attached a lucky charms).
It is the Patagonia Kids Bonsai Backpack in Spanish Moss color.
Unfortunately this exact color is discontinued but the model still remains.