What was the first form of life on Earth created from?
This is the subject of a field called Abiogenesis, which looks at the whole question of how living matter came from non-living matter.
When we look at life today, we think of DNA and supporting proteins, but one of the leading theories or components of abiogenesis is called the "RNA world" hypothesis.
In the RNA world theory, life in the form of self-replicating RNA molecules was the prevailing form before DNA existed.
This is not the only possible precursor to DNA-based life and may not be the original form of life. Various possible precursors to an RNA world are suggested, including PNA (peptide nucleic acid) or TNA (threose nucleic acid). A complementary or alternative precursor role may be provided by PAHs (polycyclic aromatic hydrocarbons). PAHs are the most common kind of polyatomic molecule we observe in the universe and are thought to have been a major component of the 'primordial soup' from which life originated.