Welcome to Just Answer and thanks for your question. What is considered normal varies slightly from lab to lab. At the one I use, normal GGT ranges from 0 to 51 U/L depending on age and sex. Next to the result on your lab slip should be your lab's reference values. We don't normally become concerned about liver enzymes until they are 2-3 times the high level of normal (102-153 U/L at my lab). It's also important to know that we look at all the enzymes together, not just one by itself. GGT can be elevated in cases of biliary or pancreatic obstructive disease (stones), alcoholism, anc congestive heart failure among other things.
Yes, they are fine with AST and ALT only being the slightest bit elevated from my lab's normal. You may want to avoid drinking and have the levels checked again in 3 months. GGT is one of the first to show changes caused by alcoholic liver disease.