You have to enjoy problem-solving and learning about science and technology to be in the field. If you want to be involved in research and development, there isn't always big money involved. If you're working at a biotech or pharmaceutical company, for instance, it can take a long time to see your work completed. You have to enjoy the process and not just the end result. Get a good foundation in physics and chemistry and biology, or design and engineering, depending on what you're going into.