The universe may be 13.8 billion years old while the Earth is 6,000 or so years old SIMULTANEOUSLY. The ramifications of gravitational time dilation (GTD) are known as Matty's Paradox.
The universe is both young and ancient simultaneously due of a phenomenon called gravitational time dilation (GTD). 2 Peter 3:8 is a mathematically accurate equation for GTD. We call it the Donkey's Jawbone.
We (that's me and the Holy spirit) deduce a theory of gravitation in which planet Earth is about 6,000 years old while the remote regions of the cosmos are at least 2.19 billion years old - simultaneously.