Are Astrophysicists Deceived?

Ask an astrophysicist how old the universe is, and you'll be told it's around 13.8 billion years old, but nobody knows for certain. Ask how they come to this conclusion and you'll be told it's based on expansion and the age of stars. EG: https://www.inverse.com/science/how-did-we-find-out-the-age-of-the-universe. My guess is that they don't really think about this stuff and repeat what they were taught.

First, how can anyone possibly know the age of a star? They don't even fully understand stars. They understand them somewhat in their present state, but that's it. All else is speculation, and obfuscated by making everything really old. All astrophysicists need to do is add astronomically big numbers in front of years and poof! Second, how can you perform a time calculation based on rate of expansion if you don't know the starting point to begin the calculations? In other words, where is the center of the universe? Nobody knows. Yet, I'm supposed to believe they can calculate how old the universe is based on the rate of expansion and age of stars. Are astrophysicists deceived? Ask them yourself.