how to become a Mega yacht captain

Hey everyone,
My name is Matt and i'm a junior in highschool and I'm starting to look into possible careers. I've been around boats my whole life, and I love being on the water my family currently owns 3 boats, for personal use. I drive all them usually every day. I've always wanted to own a mega yacht and I do think that's possible and I figure the next best thong would be to captain one of them. I work at a Marina on the bohemia river in Maryland and I was wondering what are some good steps to achiving my license. Any and all help and advice is appreciate.

Thanks,
Matt