Should I take college courses or do volunteer work during my gap year?

Answered

I find it refreshing and positive that you are a risk taker and mature enough to consider taking a gap year because a.) you know how difficult it is to get into a good American college and b.) you probably want to make your application as strong as possible.

I don't think you should use your 6 months to work on ECs in my opinion because your application to US Colleges will be judged on being an Int'l Applicant applying from the Netherlands not a US student. The context of your holistic review will be comparing you to other peer students applying from the Netherlands. You application will not be sorted and evaluated in a pool of American students who have different experiences and academics.

That being said, I think the most lacking GAPs besides ECs that Int'l students have are the following

-Course Rigor which can be either APs, IBs or College courses taken as a HS student.

-SAT or ACT test scores

Ideally what you should have done was to apply to an elite Boarding School in the NorthEast like Philips Exeter or Deerfield Academy as PG student (13th year of HS) and received an athletic scholarship for playing Hockey so you could continue doing that while taking some additional harder classes to make your application look better. I'm on a GAP year as a PG student at Deerfield and my floor mate who lives across the hall is my friend from Sweden who took a GAP year to study in the US. She is also and athlete and plays on our Varsity Soccer Team. Since boarding schools are the best ways to get into a top US college if you are an athlete, most of the ones in the NE have girls hockey teams and indoor hockey stadiums. I have some friends at Deerfield that play on the girls hockey team that received a scholarship for playing hockey in HS. While this is a rather unusual sport for most American girls, if you want to go to a Ivy League school Yale or Harvard or Cornell or a Top Liberal Arts college like Bowdoin, Williams, Amherst, Colby, Colgate, Hamilton, Middlebury, or even Wellesley they all have excellent hockey programs.

But you may know that wherever it's cold like Minnesota or Wisconsin they have great womens hockey as well.

Division 1 womens hockey rankings

https://www.uscho.com/rankings/pairwise-rankings/d-i-women/

Division 3 womens hockey rankings

https://www.uscho.com/rankings/pairwise-rankings/d-iii-women/

I might suggest you work on the following things during the 6 months you have prior to applying to colleges.

-If you haven't taken an ACT or SAT test, more often than not, submitting a high test score will improve your chances of getting into a better college. While 90% of colleges are test optional, those that submit good test scores have up to a 50% better chance of getting in because it takes the doubt factor on whether you can do the work or not. This is especially a miss-calculation for Int'l students who think its a waste of time and don't submit a test score. Because educational systems are different from country to country, sometimes submitting a standardized test score, makes it easier for an admissions officer at a college to advocate for you if they can see how you fit their college.

-I would review your transcript of courses and see if there are any weaknesses or gaps in your course rigor. Most top colleges want to see the following: 4 years of math up to Calculus, 4 years of English, 4 years of sciences including 2 labs, 3-4 years of history including US History and European History, and 3-4 years of a single foreign language like Spanish, German, Italian, French, Chinese, Japanese (the 6 most common ones). If you are missing something core, then I would sign up for some online courses that fix that gap . Again the better the courses, the more they will count. Alternatively, I personally took 2 Outlier.org courses in HS which are taught be Ivy League, MIT and top UK professors. I earned 6 college credits and got As in them. This helped my academic transcript look more complete when I applied to Columbia U. and got in.

-The third thing I would do is work on college essays. Essays are very critical to getting accepted into US colleges because top colleges are NOT a Meritocratic Process. Top colleges want great writers who can market themselves. Students who have a story(ies) to share and capable of articulating them to a captive audience and holding their attention. A smart applicant works on their essays 3-6 months ahead of when they are due. So you really should be curating a list of colleges that want someone like you and open up a Common App or Coalition App account as soon as possible. Most of the essays remain 90% the same year after year including the supplemental essays.

Feel free to google me "@CameronBameron LinkedIn". I'm the 2nd search result. You can reach out to me there if you wish.

Good luck