What can i do to join the FBI?

I'm 15 year's old and im really interested in joining the FBI in the future. i know i seem too young and am too young to join but i have a huge interest in the behavioural analysis unit of the FBI. I understand its nothing like the tv shows but its something i spend a lot of time studying but can never seem to find the answers i need. How ever i am from the UK and neither of my parents are from the usa or have ever lived over there. This is a problem as i dont know how i could become an american citizin? I understand its a long shot for this to happen but its something that i inspire to do and i believe you should always follow your dreams and try your hardest. So i need some help and some answers? Thankyou!

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Private Investigators London
Private Investigator UK