Why not try doing it without an investor? Does it absolutely require one? Could you get something going that would generate revenue and then grow it?
... or as Guy Kawasaki put it (http://www.changethis.com/1.ArtOfTheStart):
"GET GOING. Start creating and delivering your product or service. Think soldering irons, compilers, hammers, saws, and AutoCAD -— whatever tools you use to build products and services. Don't focus on pitching, writing, and planning."
i.e. make something first.
Hell I am 24 and I am not waiting for an investor to make my company a reality. If it fails, who cares, I got many years to try again :)