Is it acceptable to alter a monologue from a play?

I've been asked to recite a 1 minute monologue from a published play. The two that I have memorized from my drama class are over 4 minutes. Is it common or at least acceptable to shorten one of them or is that just not done? If the latter is so, does anyone know of a good 1 minute monologue from a play for a teen girl that isn't so overdone?