They are in Oklahoma. That is typical.
I'll be 26 in a few months, and I am not married.
From my perception, it is about half and half with my old classmates.
It is not typical for people in the middle classes here in New Jersey to be married at 20.
Honestly though, I could care less about the people I went to High School with, certainly 99 percent of them. I would not recommend worrying too much about people on face book.
The important point is, you are plenty young to fret over a stuff like this.
Take your time. It would be a much lesser hardship to have been alone for 3 or 4 years, than to rush into a marriage with someone unsuitable and have to pass the entire rest of your life with them. I'd say you certainly have the next 15, if not 20 or 23 years to think about getting married. For now, I would say work on making yourself a more elligable candidate, so as later, to have a wider selection before you.
Go to college. Advance as much as you can in your carreer. Take on a program of excercise, eat well, sleep well, and cultivate your health and body as well as your mind. Above this, expand your social circle, and surround yourself with the best people you can - moral, temperate, thinking, diverse, hardworking, educated, creative and accepting. In their company, you will surely improve and grow, and likely be introduced to a circle of women very materially superior to any you might meet leaving your chances to the wind, or at your local pool hall.
And when it comes to meeting girls, now, or later, take your time and seek out those with whom you share some common interest or goal. From among them chose who give your attention too, and to get to know better. I know churches are very active where you live. This would likely be a good place to start. Also, take classes that you enjoy as well as those you need; you will meet men as well as women who share your enthusiasms. Another likely place to begin might be communtity and volunteer organizations - Agencies promoting literacy, library associations and book clubs, nature groups are all good. You will meet more females among your fellow EMTs, but girls in general will find the volunteer firemen sexier.
One piece of advice I give to you though, is to remember: It is a much more likely thing that a women may latch herself onto a man, than that he have to exert himself to any degree to draw her to him. Beware. Chose wisely, as you too may find yourself in time, and under the influence of the flattery of being the one chosen, in a way of being very much in love as well, your time of selection and sense all behind you.
Don't sweat not being married at 20. It is so not important, nor is it an indicator of success of any sort. 
