But I'm afraid of heights! (technically not a question, but still...)
Even some of the best skydivers are afraid of heights (We love the sport, but we're not crazy!).
However, you will find that once you actually get up in the air, the ground looks like a picture. As you gain altitude, references disappear, and your sense of the height decreases. This makes the higher altitudes easier to handle. Keep in mind too, that you'll be concentrating on your training as you climb out of the plane and on into your jump. Students find that their focus is on those procedures, and not on the height.