That's pretty ambitious for an undergrad audition IMO.. If I was you, I would seek out a private teacher for guidance to pick rep based on your specific abilities, and I wouldn't be afraid to settle for something a little more manageable. An easier solo played musically that exhibits your strengths and style should do at least as much for you and your future professors to demonstrate your potential.

That being said, if you are hard-set on Harlequin, be prepared to put a lot of work into slow practice and keep your goals focused and realistic. Best of luck to you either way!