I have something very important to ask you guys...

...

Walls and ceiling and floor is 4 blocks thick. It took me three days to build

(Sorry if the pictures of the arena I built looks weird I like having my FOV set to Max)
(The floor, ceiling and walls are all 4 blocks thick.)
In the Shulker box
Helmet - Protection 4, Respiration 3, Thorns 3
Chestplate - Thorns 3, Protection 4
Leggings - Thorns 3, Protection 4
Boots - Feather Falling 4
Sword - Unbreaking 3, Fire Aspect 2, Sharpness 5, Mending 1
Bow - Unbreaking 3, Flame 1, Infinity 1, Power 5
64 arrows (I srsly don't know why I got 64 arrows when I just need 1 arrows .-.)
2 Strenght potions
2 Swiftness potions
1 Regeneration potion
4 Soulsands
3 Wither skeleton skulls
Am I ready to defeat the wither?
Oh btw this is what I have been doing for the last 3 days on SkyBlock.