Lets tackle this one thing at a time.
What is the evidence of the age of the earth?
Age of the Earth - Wikipedia, the free encyclopedia
Short answer is radiometric dating. Now how do we know that radiometric dating is correct?
Radiometric dating - Wikipedia, the free encyclopedia
If you want to know the evidence first hand then go to a lab or go read lab results.
As for the age of the sun we are able to determine it as follows.
1) know the mass of the sun.
2) Determine the composition of the sun through spectroscopy
3) Determine the rate in which helium is converted from hydrogen.
1) How do we determine the mass of the sun?
Finding the Mass of the Sun
2) How do we determine the composition? What is spectroscopy?
What is Spectroscopy?
3) How do we determine the rate in which the sun converts hydrogen to helium?
The Sun
From there its just math. And the math is there if you want to double check it be my guest.