Dark energy isn’t new. In fact, it’s been around for at least 9 billion years. According to new data gathered by the Hubble Space Telescope, this mysterious force was already working to speed up the expansion of the Universe when it was only a few billion years old. Hubble measured the light from 24 of the most distant supernovae ever seen, and found that the Universe is further apart than it should be if only gravity was around to slow things down.
Hubble Finds Evidence for Dark Energy in the Young Universe

https://www.nasa.gov/mission_pages/hubble/news/dark_energy.html