I have been a PM for about 30 years after about 10 years as a programmer/analyst. I have an Associates Degree in Computer Science and 3 years ago I got my PMP certification along with MS Project/Project Server certification.
I got into PM through the IT field and discovered too late that Project Management by definition is a temporary postion. A project has a start and finish so it is possible (and in a lot of cases probable) that when your project is complete youw will be out of work.
Some companies have enough work to keep a PM on staff others only hire temps to do the PM effort in that they can let them go at the end. Projects can run from months to years and I've had both kinds along with projects that were suppose to be over a year and cancelled after a month or two (and thus out of work).
Since PM's are generally well paid they are also the areas that are cut first in an economic down turn.
Since I've painted the worse here is the best. The field is always changing and you get to be in on the new technologies. You are generally in charge of your own success and are challenged every day to be the best facilitator possible between upper management and the technical staff. On the whole it is a lot of fun and you can really go into any area your are interested in. In my case I like the technology and I can learn new languages and methods while managing a team developing something that will benefit the company.