Protostar Stage
The first stage of stellar evolution is nebula.
stellar nebula
A nebula is the initial stage in the lifecycle of a star, a vast cloud of gas and dust in space where stars are born. Gravity causes regions within the nebula to contract and form protostars, which eventually grow into full-fledged stars. Nebulas are the birthplaces of stars in the cosmos.
It doesn't differ from a star, it is a star and it is the second stage in a stars life after the nebula stage.
The Nebula
The first stage in a star's life is as a nebula. As the gravitational forces spin faster, the star enters it's second stage, that of a prostar.
Gas
Nebula
hydrogen and helium.
A star is "born" in a large cloud of dust and gas called a nebula
No, a neutron star can't become a nebula. A neutron star is not made of atomic matter, has less mass than a nebula, and has no mechanism by which to expand.