Thanks for your answer BillinSD.
I though that high liver enzymes was related to how many damaged a liver can have. But, your explanation (and some research online where I saw that even on cirrhosis of the liver, enzymes could be on normal range) so basically there's no way to find out how damaged is my liver already
I know you can recommend liver biopsy, but I also read that even liver biopsy is not so accurate like people think, the reason is the person which performs the biopsy could insert the needle in some space of your liver that is not very damaged meanwhile probably on another side of your liver you could have cirrhosis, so someone could be missdiagnose as mild fatty liver and could have earlier cirrhosis...
But with this normal liver enzymes on my side, no doctor is going to prescribe me any liver biopsy anyway. (and since biopsy is not accurate either, is not very usefull).
So, there's no really a good way to know if this fatty liver is very damaged or not
which is kind of sad to know.