I have been looking into the earliest possible time in the universe that a human-like intelligent species could evolve based on the necessary elements being present.
Kepler-444 is one of the oldest solar systems with rocky planets that has been observed. It is 11.2 billion years old and although the planets are too close to its star for life as we know to develop, its existence means that habitable rocky planets could have existed at this period of only 2.6 billion years after the Big Bang.
As we go further back in time the metallicity of stars becomes much lower, so the chances of a solar system forming with all the necessary elements for complicated life will be very unlikely but as we have learned more recently, supernova are only responsible for creating elements up to the heaviness of iron and all the heavier elements are likely creating in neutron star mergers.
This makes me wonder: could neutron star mergers can raise the chances of a solar system existing with the necessary elements for earth-like life at the time of the population III stars when the universe was only hundreds of million years old? Such solar systems might be very rare but are they possible?