Like some have said...why in the hell did you accept the job being paid under the mean?
If it was b/c of lack of experience you still don't have the experience.
I find this thread of interest to me. I accepted my job well under the mean, due to it being my first job out of college, and I had to learn the technology. Now that I am a year in, I am expecting to bargain to get closer to the mean. Did I screw up by starting out so low? Or did I follow a protocol similar to several, where I took what I could get?