Chyna,
Welcome to APUG! Glad your here. Go for it! Study photography, become a photojournalist, and don't let anyone dissuade you.
What I am about to write is only my opinion and you should take it as that: just someone's opinion. First, I work professionally for a wedding photography studio in Chicago. Codes of practice for photographers with in it are this:
1. Whatever the bride wants she gets.
2. When people put on formal wear their brains fly out the window. For some reason, fancy dresses and tuxedos make people forget how to listen, concentrate, and smile.
3. There's no reasoning with a drunk person.
4. Brides and grooms say they want NO posed pictures (called photojournalistic style), BUT they are LYING. If you take no posed picture, they will complain guaranteed. At their consultation, point out that they do want some posed pictures and they usually agree.
5. Here's the typical set up for backdrops and alter shots. Two umbrellas 45 degree angle, blast with light, and no shadows. If there's a shadow, they'll complain.
6. Every photo must have the person looking right at the camera and smiling or its no good.
7. Weddings are static photography: stand there, look at the camera, say cheese, and smile. Not artistic, but there's alot of money to be made as a wedding photographer.
Second, I have been doing portraiture since I first picked up a camera. What I want to say is this: don't follow anyone's standards for how or how not to shoot portraits. Learn the technical (how to use lights/strobes, f stops, etc.) but never, ever let anyone make you believe that you have to follow a dictated method or style for portraits. Break all the "rules" and laugh at how the big time portrait photographers make their images look the same. Before you make an image, think "What can I do to make this better?" An idea of the moment as we say.
Third, I don't know anything about scientific or illustrative or photojournalism for magazines or papers. I do have an opinion about photojournalism for papers and magazines. That is, be careful. Photography is not reality. Let me repeat that, photography is not reality (that's a fact not opinion). It's a fraction of a second in time that's manipulated by the photographer (composition, angle, light). You can take a picture one second and the next take another picture that contradicts the one you just took. Keep that in mind when you see picutres of war, politicians, beauty contests, parades, etc. They're just a fraction of a second in time and don't tell you anything about the real situation, movtives, or further actions of people or things.
So much for making this short, but welcome!