At 18 years of age, you have your whole life ahead of you! The maritime opportunity sounds great, and IMHO you would be crazy to turn it down! You can learn a profession, see the world, fill your boots
and have some amazing life experiences, which will make you stand out from all the other hundreds of 200 hour aces, graduating from the sausage factories in Oxford & Jerez.
Integrated or Modular, that debate has been done to death on these forums. It's horses for courses at the end of the day. The biggest risk for new Pilots these days is, not getting their licence, but getting their first job. A lot of guys & girls get lucky, many do not! Having a Plan B is very important, and you seem to have some very nice options.
Whatever you decide, I wish you the best of luck! It would be very interesting to hear how things pan out for you over the course of the next few years!