At my son’s school AP language is not available, so he had the choice to take a 4th year of foreign language and give up Valedictorian or take an AP class, skip the fourth year of language and be Valedictorian. The AP class is in a science and much more difficult than the foreign language class he would have taken.
This is from the Stanford website,
"We do not have a required high school (or college) curriculum, but we do make recommendations. We expect freshman applicants to have engaged in a rigorous curriculum and chosen from among the most demanding courses available in their secondary school. It is not necessary to take every advanced course offered; but if such courses are available to you, we expect that you have taken advantage of many of them. Our most competitive freshman applicants often have four years (grades 9-12) of English, four years of math (including calculus), four years of social studies, four years of science (including biology, chemistry and physics) and four years of a foreign language.
There is flexibility, however, in how we view an applicant’s curriculum. For example, an applicant may be competitive with just three years of a foreign language through 11th grade but also with five math courses taken in the last four years. Conversely, an applicant may be competitive taking two languages all four years and just three years of social studies."
http://admission.stanford.edu/basics/selection/evaluate.html
I wouldn’t do the early out unless you are doing dual enrollment or had some really good excuse. Colleges want to see the toughest schedule all the way through.