I am pretty sure that MIT admissions will understand the grading system used in Scotland.
However, I would not expect MIT to accept any more than one or two students from Scotland in a given year. You will need to be close to the strongest student in your high school at least in math and science to have any realistic chance of getting accepted to MIT. As an international student at MIT I never met any students from Scotland, but that might have been either a coincidence or based on the high quality and relatively reasonable cost of the excellent universities in Scotland.
Being able to pay for education in the US as an international student is an entirely different issue.