Great chatting with you just now! It’s a really good question and one I wish I had the answer to. It’s hard to know exactly why life started on earth or even how.
There are many theories about how life started, but I believe that the right ‘ingredients’ to make life just happened by chance to be close enough together at one point to make the most basic life. This then evolved into the complicated organisms that we know today.
Does this answer your question or have I got the wrong idea?