I recommend gut wanting to try a beard to let it grow for at least 13 weeks without trimming other than a neckline. Many guys start out looking thin and patch can end up with a good beard in time. Also, blondes and reds do not appear as full as darker beards, so don't let the color fool you. When short, the beard color has little contrast to the skin color and it looks thin. Once it gains some length, the 3'd effect will start to make it look fuller.
Pretty patchy and scruffy looking. Letting it grow will probably just look scruffier. Depends on the style you are going for. IMHO, you would look much better clean shaven.