The fashion industry is great, and modeling can be a passion. Starting when you are a teen can be a really good way to go at becoming a model.

[edit] Steps

Tell your parents that you are interested in modeling. If they object, then just leave it there. If they think that it sounds good, then start working toward it.
Research local modeling agencies on the computer. Find a modeling school. You can't be a model without any experience.
Show your parents what you have researched and found out.
Make sure you have all the information, like how much it costs.If they choose to let you take the class, then your teachers will help you from there. But if your parents won't let you, there's still hope!
Take a lot of pictures of yourself, and post them on your MySpace/Facebook. Try different poses and facial expressions. See if people comment on them saying stuff like 'OMG you should be a model'
Practice making your own runway walk. Make it your 'signature walk'.
Then once you are older, you can put yourself out there into the modeling world.

[edit] Tips

Modeling schools are VERY expensive. (Ex. $1,000+) But it can be worth it in the long run. Make sure you really want to model before you invest that kind of money.
Just because you go to modeling school does not mean you will be a successful model.
Be careful of people who will tell you anything to get your money
Be careful of people on Myspace and Facebook or sites of the like
Most modeling careers end after your twenties so have a back-up plan after your modeling career