Would stars be considered asteroids?

No.

An Asteroid (also called Minor Planet) is one of many small bodies usually sizing from 480 Miles (755km) to less than one mile (1.6km) and usually revolve around a Sun. They are inactive therefore only reflect small amounts of light and give off none and are made up of rock. They originate from the beggining of the universe or have broken away from other planets or exploding stars.

Stars are luminous bodies like our own Sun which are usually the centre of other orbiting bodies or planets making up a solar system. They are very active generating massive amounts of energy mostly in the forms of Heat, Radiation and Light all due to the nucleur fusion generated from the core of the Star.