That will depend on whether those values are really zeroes or missing value. If those are "missing values" - the need to be excluded and the count drops. If those are really zeros then those need to be included in your calculation of average.

Do not include zeros in average Excel?

To exclude zero values, you'd use the criteria <>0. Specifically, the function in C6, =AVERAGEIF(B2:B5,"<>0"), averages the values in B2:B5 only if they don't equal 0. Column B uses the traditional AVERAGE(), which includes zero.

Do you include 0 in standard deviation?

This means that every data value is equal to the mean. This result along with the one above allows us to say that the sample standard deviation of a data set is zero if and only if all of its values are identical.