The universe is always saying it’s younger than it really is

According to measurements of the cosmic microwave background radiation (CMB) by the European Space Agency's Planck mission, the universe is about 13.8 billion years old.

 This calculation is based on what's known as the Standard Model of cosmology, which describes a flat universe dominated by dark energy and dark matter and which is expanding at an accelerating rate. 
The Standard Model is then used as a basis for supercomputer simulations that can depict the growth of large-scale structure in the universe — galaxies, galaxy clusters and huge chains and walls of galaxies. 

But!!

In a new study, astronomers led by Guo Qi from the National Astronomical Observatories of the Chinese Academy of Sciences studied pairs of satellites in galaxy groups.
Galaxy groups are small collections of galaxies, such as our own Local Group, in which a few large galaxies are joined by a swarm of smaller ones. Like larger galaxy clusters, these galaxy groups form where filaments in the cosmic web of matter that spans the universe meet, with smaller galaxies moving along the filaments before falling into a group.