The right front bearing went bad at 48,000 miles, is this normal & why?

No, this isn't normal. Part failures can occur at any time regardless of age or mileage. You should expect the other side to last longer though.

AGREE WITH BAK

5 Yr./60K on drivetrain. Sad but it only takes a small pothole to trash some bearings. Get it replaced at a dealer (should be warranty) and go on and enjoy the ride. IF there are any doubts , as far as the cause of the noise , get to test drive WITH the tech who will be working on it!