An abstraction of the life cycle of sun mapped in the Hertzsprung-Russell Diagram.
As the white passage shows, our sun started as a cooler red star on the lower right side of the diagram.
It is currently in its prime stage of its life cycle, a bright yellow star on the “main sequence”.
Billions years later, after its core energy depleted, sun will first expand and them cool down to a white dwarf at the end of its life cycle.