This comment confused me at first, but I think you're being complimentary? If so, I think you'd want to use 'first rate' to mean something best in class. Firs

This comment confused me at first, but I think you're being complimentary? If so, I think you'd want to use 'first rate' to mean something best in class. First grade is well, first grade(childish), at least in US English.