For every grain of sand on every beach on Earth there is a star in the univese
The oldest stars are classified as population III stars [See related question]
The oldest stars are classified as population III stars [See related question]
Population II stars are the oldest in our Milky Way. Population III stars were the first stars in the Universe, but have yet to be discovered. See related question
The youngest stars are protostars which are still forming within giant molecular clouds. The oldest stars in the universe are believed to be Population II stars, which are remnants from the early universe and can be found in globular clusters.
Stars are scattered all across our universe but guess what? there are no stars in our solar system besides the sun!
The Universe.
A galaxy contains billions of stars. A universe contains billions of galaxies.
All stars and galaxies are in the universe.
Shortly after the big bang, the first stars were formed - Population III stars. These comprised of nothing more than hydrogen and helium and maybe a little lithium for good measure. When these stars died, they would have exploded as massive supernova and spread the first 26 elements into the Universe. These 26 elements would have mixed with hydrogen and helium to make the next set of stars - population II stars. Most of these stars, when they died, would have exploded as supernova, enriching the Universe with the rest of the elements. These elements, along with even more hydrogen and helium, combined to make our Sun. Our Sun is a metal rich star or population I star. Just in case your wondering what the next set of stars will be called, I have no idea - Population 0 maybe?
The Universe.
Stars do not belong to a planet. They belong to the universe.
We haven't observed all of the stars in the Universe, so we don't know what is the largest yet.