I'm in a similar boat, also preparing for my first 5 mins.
One thing I've been conscious of, which may/may not be a problem for you, are little things like mimes/gestures. For example I intend to do a few bits which involve two arms so at some points I need the mic on the stand... but for the most of it I want the mic in my hand. Last thing I want is to get muddled up with my hands/microphone.
I don't think you have to be doing stand up for a year just to get a 10 minute spot as you have suggested. At the "beat the frog" competition in Manchester if you win the competition OR impress the club then you get to do an 8 minute spot for free..... and I've some very average acts get the privilege of an 8 minute spot.