I would be very happy with 5.1
But I would always want to know the Triglyceride levels (but that needs to be from a fasting cholesterol test).
Did they give you the other figures?
Docs have the idea that diabetics should be lower that that, as has been shown above.
But since cholesterol levels have now been shown to be a poor predictor of heart attacks, and there are numerous other factors at work, including Trigs and HDL, and ratios, I think most GPs are basing their recommendations on seriously outdated info.
If you follow the link in my signature to the bloodsugar101 website you will find plenty of recent information on the subject.