Reachable goals. Long & Short term

Well I think I am to the point where I should establish some sort of goals. (I have goals listed in my signature but those were made right after joining and without much consideration). I have read on multiple forums that guys who start off bigger have a more difficult time gaining. This worries me, not that I view myself as being big, but I have noticed from what averages are posted that my starting measurements (also listed in signature) are a bit above average.
Does this mean I will have a more difficult time making permanent gains?
Are the goals in my signature realistic, or should I back them off a bit?

I know I won’t have a basis until after first months measurement. I would just like to get some opinions on setting reachable goals. Any advice would be greatly appreciated.