time there are plenty of protons and other light nuclei in the universe, and
there are also plenty of electrons. But until now, the Universe has been too
hot and dense for the electrons to be captured for very long by a nucleus, without
being smacked out of orbit by collisions with other particles.
temperature of the Universe cools to the point where the average speed of an
average electron isn't high enough to escape capture by a proton, then atoms
start to form. Since the only nuclei that exist are hydrogen, helium and lithium,
the first atoms to exist are therefore hydrogen, helium and lithium.
elements, such as carbon which is necessary for life as we know it to evolve,
are created in a much more interesting manner.