Want to live my dream? but how?

So, I'm 13 now and I want to jump start my career NOT now. But when I'm 18. (When I'm a adult) and I have a question that how can I "jump-start it" it is so hard to just do that. I dont want to do it in a young age becuz stars on Disney Channel now, wait 5 years and nobody will remember them. So older the better. But how would I even be abel to jump-star it??!?!?! lol I live in CAL so I can go to hollywood but WHAT Talent agencies are their? please answer this question I'm longing to know!!