I think is better to say that there are strong signs that heterotrophy preceded autotrophy.
The earliest Earth was rich in organic compounds from meteorites and comets bombardment.
The earliest atmosphere had no, or very little, oxygen. The organic compounds were not oxidized. Metabolism could not be aerobic.
The molecular studies with archea and bacteria, seem to allocate heterotrophic as the oldest.
Fossils of apparently heterotrophic prokaryotes, precede in 300 MY the oldest known stromatolyte fossils: 3.8 to 3.5 billions years respectively.
I think these are correct, but sure there are more.