Your accomplishments are very impressive. I don’t do chance me’s, but here area a few comments…
- Be careful with programs like Global Young Leaders Conference. IMHO, I don't think it will be given much weight. Here's an article you should read - it's a few years old, but still applicable.
http://www.nytimes.com/2009/04/19/education/edlife/leadership-t.html
- Make sure you list your ECs in order of importance to you. The list should be ordered in such a way that it supports your overall application narrative.
- You also need to include how long you've been doing the activities. It makes a big difference - 4 years shows commitment. If you've done things for an even longer time, that's even better.
- Three of your skills are actually extracurriculars....and then under Misc, you have four more extracurriculars. IMHO, GYLC should not be above editor of school newspaper. Don't forget that you do not need to include all 17 extracurriculars. Again, take time to think about your story - which ECs are going to make your application stronger? Which ones are just extra words?
- Your ACT is a bit low compared to the accepted class of 2021 (average 33) - I think your composite is a 31. You may want to take it again. Dartmouth does not superscore the ACT, but you can send your highest composite score.
- What about your recommendations? You need two teacher, a counselor and an optional peer rec. Make sure you get commitments for those locked up now.
- Also, take a look at the essays Dartmouth asked this year.
https://admissions.dartmouth.edu/apply/choose-your-path/early-decision/essays
FYI the prompts were released at the end of July last year, so keep an eye out for them again this year.
- Besides that, make sure you research Dartmouth well (know its strengths and what makes it unique) and craft a narrative that shows that you will be an excellent fit.
Best of luck to you.