DO NOT trim/shape your beard prior to the three-week mark. I recommend waiting at least four weeks before shaping. If you trim too soon, your beard could become lopsided. ... When first growing a beard I let it creep half way down my neck and then draw the line.
Should I shape my beard or let it grow?
You can't rely solely on your barber to keep you looking orderly, you certainly shouldn't grow it out without ever manicuring it into a sculpted and flattering shape. It's also necessary to trim it often, even if you're in for the long haul. Trimming a beard prevents flyaways, split ends, dryness, and dishevelment.
How often should I shape my beard?
While there's no hard and fast rule as to how often you should trim your beard, you'll probably need to do this at least once a week. If your beard's really detailed, then it's likely to be more like every other day. When it comes to shaping, try do define the natural line of your beard.