Why not all of the smallest particles have ALWAYS existed as have the laws that govern their behavior?

Question

Why not all of the smallest particles have ALWAYS existed as have the laws that govern their behavior?

Answer 1

'Always' means time had no beginning. If you're comfortable with that, OK. Nobody can prove that it did or did not.

Answer 2

In the beginning, about 15 billion years ago, there was the Big Bang....

Far away galaxies are moving away from us, from which astronomers have deduced that the Universe expands and that it was very hot and very dense at the start. The elementary particles (photons, electrons and quarks) formed a plasma so hot that they couldn't combine.

As the Universe expanded and cooled off, more and more complex structures were formed: protons, neutrons, atoms and later on stars and galaxies.