Ok, in my opinion it is far too self-conscious and "clever" to be a piece with which you can just let yourself perform to the absolute best of your ability.
It is also very stoic and british, with allusions to other literary texts (notably and obviously Hamlet but also others). The absurdist style in which it is written also wont transpose well to an empty stage (other than yourself) and you will no doubt have trouble finding an excerpt with enough interest to hold you through the whole rehearsal period.
In short, I think it's a terrible text for a solo performance, and you are better off doing something perhaps more "cliche" but with which you can connect and create depth in.
Remember, this is your final school drama performance. If you genuinely love the play, then perhaps it would work, but it's no use choosing something high-brow and boring the audience to tears...
There are so many awesome monologues for guys, it's all I found when I was looking for pieces for myself. Have another look around.
