My advice is simple, don’t do what I did. Follow your dreams, no matter how ridiculous and unattainable they may seem; just do it! Not to quote Nike, but it's true. I became a model because it was a secular dream of mine after becoming a firefighter. I want all young girls to chase what makes them feel special, confident and at peace.
If you decide to take up modeling the one thing I can say with certainty is: DO NOT PAY FOR PHOTOSHOOTS OR AN AGENCY!
The agencies all look at young models as cash cows. I have had multiple interviews with multiple agencies and I have never been turned away until the conversation turns to fees. I have not, and will not, ever join an agency, I market myself better then any agency could, and I managed to keep my freedom. (Hence the name free-lance model)
Let me make this loud and clear if someone wants YOU as a model to pay for anything (and I mean anything), DO NOT work with them. If you are a hired model, you are working as a paid commodity which means you should be leaving the set with cash or cheque in hand.