Ok so... going double hit:

Lit new torch: 19

First hit
Me: 18

Zombie: 18

I win cause of higher agility.

Damage: 4 + 7/2 -3 = 5 damage. /2 cause of resistance. I do 3 damage on first strike.

Second strike:

Me: 7

Zombie: 17

I miss my attack....

Well at least I did some damage.