Tall players sometimes have trouble getting down to hit their shots, especially since the table is rather low for their height. However, it can be hard (and painful) to bend your knees that far.
Instead, spread your legs and stance wider — especially for a forehand — to get better oriented to the ball, and to let you drive your weight through the shot. I call it “playing large,” and it will let you be just as athletic (and even more powerful) than less tall players who may seem more naturally suited to the sport’s dimensions.