Actually, that's not quite true.
20 years ago, give or take a few years, the consensus was that the Universe was somewhere between 10 and 20 billion years old. There was a fair amount of "slop" in their estimates at that point in time. Today, they have more refined techniques available, and much more data. So they now think it's about 13.5 (+/- 0.5) billion years old, which is well withing the estimates of 20 years ago.
I apologize, I was engaging in a little hyperbole.
Just trying to make the point that an argument from consensus is flawed.
They all come to the same conclusion because they all use the same model.
But there are huge assumptions underlying the current popular model, most of which still have little support.
Thus I'll bide my time and keep a jaundiced eye on the whole endevor.
For instance the use of a globular cluster to arrive at this data point is fraught with difficulties since the age distribution of stars in globular clusters varies significantly from that of our galaxy.
We have no idea how they form.
Or even why they are where they are.