Can you tell me the z score for the following numbers?

10, 12, 16, 18, 19, 21.

Thanks, I am getting the wrong answer each time I do it.

mean = sum/6 = 96/6 = 16

10 - 16 = -6
12 - 16 = -4
16 - 16 = 0
18 - 16 = 2
19 - 16 = 3
21 - 16 = 5

n-1 = 5
s^2 = (1/5)(36 + 16 + 0 + 4 + 9 + 25)
s^2 = (1/5)(90)
s = 3 sqrt 2 = 4.24
-6/4.24 = -1.42
-4/4.24 = -0.94
0/4.24 etc