you may not be able to get work experience in the relevant offices, as some places do not accept work-ex placements if you're under 18, but you could try contacting your local paper or radio station and ask if you could look around.
Explain why you want to visit, and they will probably arrange a visit for you. and while you're there ask how they got started, etc. At the very least they should be able to give you some advice over the phone or via e-mail.
good luck