PR4 is a decent PR (i got the same situation) as grg (btw, you have a heck of a nice avatar lol) said. I am always happier when a i get a better SERPs ranking tho
Thats not to bad, my blog just got a pr4 to and now has PR6 sections! You can see my blog near my username
4 is medium, but is certainly nothing to be ashamed about. Work on making the grade to 5 and above, which won't be as easy as the move from 0 to 4
That's pretty good for starting for the first time. Keep working on improving the ranking in times to come.