Can I follow in my Dad's footsteps?

Hello, I need to say straight up that I am not a mariner, but I would really appreciate some advice and I don’t know who else to ask. I live in England, my Mum was English and my Dad American. We lived in Massachusetts until I was 10 then my Dad was lost at sea. My Mum and I came to England and we were ok until my mum got cancer. Now I am 16 and out of foster care and really, really want to have a career at sea. I am doing well at school and have a part time job. Three days a week from 3.30 am til 8.00 am I work at a fish market mainly cleaning the stalls and gutting fish. A lot of people think I want to go to sea just because of my Dad, but that’s not true. I can’t explain it well but I love the sea, the smell, the feel. I am scared of its power but in awe of it too. I feel like me and at peace. I haven’t been on a big ship, but I have been out on deep sea fishing boats. I am very serious about being a mariner, please don’t think I’m just a kid, I am 16. My aim would be to work on a container ship but I know I have to work up to that. have an American passport and would like to know the best way I can get some experience. I don’t have money to live and study in the US so I will need to work. Am I being stupid to think I could get work on a ship? What can I do to improve my chance of employment?
Thank you.