first class

Good morning, everyone.

Yet one official from Stanford University liked what he saw in the young man – hard work and a desire to learn new things. At the time, Stanford University was just getting established. It admitted Hoover into its first class.

Source: VOA Learning English - America's Presidents - Herbert Hoover: Blamed

What does "first class" mean in this context?

The first group of students to be admitted, when the university was new.

Which would also, four years later, become the first graduating class.

In the standard American system, undergraduate degrees take four years to earn, and the students in that first "entering class" would progress together for four years and become the first "graduating class". He graduated in 1895 and so he and his fellow graduates that year were collectively called the Class of '95.