Is 18 to old to start Modeling?

I really want to be a model. I imagine myself on runways for high fashon (ex. Versace, Dolce and Gabbana, Vogue, Cover Girl). I'm 14 years old but my parents don't want me to model. So I was thinking of starting once I was old enough to move out. Would 18 years old be too old to start? I could start practicing now, but I don't think I can model until I am in control of my life completely.