Hey there, well it's pretty hard to pin point when you might have got HCV just based on your biopsy results. The disease can be very slow moving. For example I had my first biopsy in 2003 and I was also Grade 2 Stage 2 and I had probably been infected for 20 years.
Also the disease moves at different rates; just because it took me 20 years to get to G2S2 doesn't mean it will take me another 20 years to get to cirrhosis. People have been known to go from Grade 2 to Grade 4 in 2 years.
You would need to look at when you may have been at risk eg: any blood transfusions, vaccinations, tattoos, IV drug use, dental work etc to get an idea of when you may have contracted it but there are many people who have no idea how they got, or when... Despite blood being screened for HCV since 1993 I have heard of people who have contracted it after that via transfusions.
Others may chime in with more info....
A few people know for sure how long they've had hep c, but for most it's a "best guestimate." What makes "time of infection" so hard to pinpoint is that the virus not only affects everyone differently, damage to the liver does not appear to follow any predictable timeline. It's presumed that stress, tobacco and alcohol are bad for the liver, but how quickly and in what amount they do damage is not clearly understood.
You'll find that you'll be better served looking forward than looking back. You're certainly at a point where there are many factors and things to learn and consider. It's a great first step that you've quit the drinking and smoking, and I wish you the best.
~eureka