I think the other posters have summed up most of the good and bad points. You get paid to have a good time. It's a thrill and a turn-on, you meet some interesting people (and some complete idiots), and if you go on to do duos etc, you get paid to have sex with some seriously sexy guys and/or girls.
However, you can guarantee someone you know will see it. Some people can't take the pressure and sometimes turn to drink or drugs. There are also health risks involved unless you stick to solos. It can also have an effect on your future career and relationships, not to mention your sex life. You've got to assume that at some point your current/future partner will learn that you've done porn, and that can ruin relationships. Another thing to consider is that the longer you're involved in porn, the more likely it is that you'll become jaded and get into more extreme sex, and plain vanilla just won't do it for you any more, which will affect any relationship you might have in the future. That doesn't happen to everyone, but it does to some.
The other thing you have to consider before starting is whether or not you'd like your mother or baby sister to see the pictures or vids or know that you're a sex worker, because any way you slice it or whatever spin you put on it, as soon as you accept money for performing any sexual act, you're rent.
I did porn for a while a few years ago. One of my colleagues bought a film I'd done and soon everyone I worked with knew a hell of a lot more about me than I really wanted them to. At the time it was pretty stressful, but it could have been worse. After a while, people didn't stop talking when I walked into a room and stopped whispering in corners and looking over at me and I just got on with life. Some people haven't been so lucky though. I enjoyed the work. It was a bit seedy occasionally, but it was fun all the same. It's quite a thrill to see your film on the shelves too, but every now and then when you walk down the street and some dodgy old guy gives you a funny look, you think, "Was he wanking over me last night?"
My advice? If you really want to do it, go for it, but be prepared for any consequences. Think it through carefully and don't let other people pressure you into doing it.