What is the first ever year?

There isn't a definite one - it can't be meausred to that precision.

For human history and Archaeology the BC / AD system is used, and is analogous to the use of 0ºC for everyday temperatures in taking a familiar but purely-arbitrary reference point, although with all-positive numbers for both BC and AD.

Geology and astronomy use a similar past-going but positive-number count as thousands or millions or years BP (Before Present), which I think is actually 1958. The 55-year difference between 1958 and 2013 is vanishingly small, far below the calculation tolerances.

It's also expressed by geologists as so-many ka or Ma (thousand or Million years ago, respectively.