It's pretty average… most riders will have a 4.8 or higher. Anything less than 4.7 and you will start seeing it take longer to get a ride, because drivers will begin declining to take a ride from someone with a rating so low.
Does my Uber score matter?
Any lower than 4.6 could be a potential issue, because it's at this point that Uber can consider deactivating your account. Consistent low ratings are monitored by Uber. If your score remains low for an extended period, Uber may cancel your account or ban you from working with them.