Word of advice here. I spent 15 years of my life working as a marine fisheries biologist for NOAA in Seattle, Alaska, and Washington DC. before getting married, relocating, and getting into teaching. An undergraduate degree in marine science gets you nothing in terms of a science career. At a minimum you are going to need a masters degree for entry level policy oriented jobs and a PhD for any serious scientific jobs in marine science. There are some alternate routes like ocean engineering. But if you are thinking you want a career in marine science, you are looking at graduate school. So you should be looking at undergraduate schools that have a high placement rate for students going into top PhD research programs in the sciences.
Also, most of the money and research jobs in marine science and oceanography are related to climate issues and things like chemical oceanography. Studying things like CO2 absorption and productivity. And not things like studying dolphins or coral reefs or such. If I was your age and looking to start a new career in ocean sciences, I’d be looking at climate change adaptation, which is as much engineering as science. Cities and countries around the planet are going to be paying enormous sums of money to science and engineering firms to help them engineer against rising sea levels and such.
What does that mean for you, just starting a career in marine science? It means finding the best biology programs you can find as you are going to need a core undergraduate education that is heavy in both biology and chemistry. Don’t be obsessed with finding a program with a top marine biology department. You just want a top biology program that has marine science classes available. You are likely not going to take more than 3 or 4 marine science classes anyway as an undergrad. And there are a lot of interesting summer programs you can do around the world. Then gear up a good undergrad research portfolio that will impress grad schools and think about graduate studies at one of the top 5 marine science programs in the country (University of Washington, UC-San Diego, University of Miami, MIT, Oregon State, etc.)
In your shoes, I’d be looking at the Ivies and near equivalents with top undergrad biology programs with the idea that the purpose of your undergrad experience is to launch you into graduate school, not directly into a career in marine science. Of course all things being equal, it doesn’t hurt to find one near the ocean so Stanford, Duke, Rice, etc. and not Washington U. or Northwestern in the center of the continent.