Olivier Rochus at 5' 5" got to #24 in the world.
Don't worry about it.
Benjamin Becker is 5' 10" and was one of the hardest servers in the world.
If you are 5' 9", maybe you might top out at 134 mph first serve speed (if your form is good enough).
Lots of advantages to being shorter and quicker in tennis offsetting advantages that taller players have in certain areas.