At 11, I think having an arsenal of five pitches is a bit much. You would probably be best served to focus the majority of your efforts on mastering the 2-seam and, to a lesser extent, the changeup. Get totally confident in those pitches, see the movement in them, be able to throw them to any quadrant in the strike zone in any count.
In Derek Johnson's book "The Complete Guide to Pitching"
, he talks about the difference between "owning" and "renting" a pitch. It's okay to work on your other pitches, but you must absolutely master, or "own" one or two.
Here's the relevant section:
[i]Owning Versus Renting the Pitch
Pitchers need to understand the concept of “owning versus renting” the various pitches in their arsenal. As mentioned before, it is common for young pitchers to adopt the various types of pitches that their favorite big leaguers throw, and they sometimes end up throwing four or five different pitches.
Unfortunately, the young pitcher can rarely master and command his full repertoire. Though he is capable of throwing a certain pitch, he may not be able to throw it for a strike very often, and the pitch presents no real threat to the accomplished hitter. This condition is called renting the pitch. The pitcher has the ability to throw the pitch, but his inconsistency and lack of command with it make it a low-percentage strike pitch. In other words, the pitcher can’t rely on the pitch in a crucial situation; it is not a sure thing, and he is therefore renting the pitch. Owning the pitch means that the pitcher is sure-minded when throwing it. He is able to throw it in any count or situation, and he places full trust in its action and his command. An owned pitch is one that is thrown in the strike zone more often than not (high strike percentage) and one that will force the hitter to make a decision to swing or not. This is an important distinction for the pitcher to make as he is preparing the tools for his arsenal.[/i]