There are 2 factors involved in the seat-to-ground distance. One is seatpost height, which should put you right with the pedals. The other is bottom bracket height. If your bike has a high bottom bracket, it may well be that your tiptoes won't touch comfortably when on the saddle. That's OK. You may be perfectly fitted to 2 different bikes and the two provide different saddle-to-ground distances. Don't adjust your saddle based on ground distance. You should learn to dismount by standing on one pedal and stepping to the ground with the other. A high BB is good in that you can peddle through corners without worry of striking a pedal on the ground.