Hello and thank you for your question,
Yes, your gastroenterologist is correct. Your liver should be biopsied every few years to keep an eye on the amount of scarring present in the liver.
Because auto-immune hepatitis causes destruction of liver cells, it puts you at risk for developing cirrhosis. Best way to diagnose cirrhosis or to tell what health your liver is in is to do a biopsy.
Biopsy is not at all harmful to the liver and will not cause any damage if done every 2-3 years.
I hope you find this information helpful. Please feel free to follow-up with any other questions you might have.
If you are satisfied with the answer, please do click 'Accept' button so that I may get credit for my work.
Best wishes and good luck,