I second all the encouraging opinions here - and would add that I knit for many, many years before I worked up the courage to knit my first sweater and now I rue the years I spent making rectangles (scarves, dishcloths, etc.).
There is nothing more inspiring than knitting something you would want to wear and realizing it's just not that hard. If you can read the pattern and pay close attention to what's on the needles, you won't have any trouble.
Plus, that sweater is amazing - can't wait to see what color you pick! (be sure to choose a decent yarn!)