Hair on the face, like every part of the body, grows at different rates.
May I suggest that, instead of shaving it off, you get one of those beard trimmers, set to the lowest setting and keep triming the hair to a short length?
Eventually, the slower growing hair will catch up with the faster and you'll have that 'designer stubble' look.
As for growing a big beard, forget it. Most men can't grow those full husky beards. For many, it tends to grow in patches and splits in the middle of the chin to create two straggly tails.
I know a Muslim gentleman who is in his 60s. He is such a nice chap in most ways, but he is so self conscious about the way his beard splits. (He's also incredably tight with money. But a good friend for all that and someone I would trust).