** Let’s review your plan:**
- you're a Portuguese HS senior now
- wait to apply to elite American schools until after senior year, to enable senior year grades to boost presently lackluster GPA, and study for SAT/ACT, etc ( which you are confident you will get very impressive scores).
- use gap year work on a canned, killer EC project out-of-the-blue to impress the admissions committees, because you presently don't have much EC involvement during high school
- get admitted to a elite American school that will give a large FA package, then graduate w a math-related undergraduate degree
- get hired in the US without US citizenship/PR for a math-related job, with only an undergraduate degree and no relevant work experience.
- work a few years to get experience and then get admitted to an MBA program in the US ( I'm assuming you also expect a generous FA package for international students)
- graduate MBA, get an even better job, get PR
Am I missing anything?