Your application is probably as strong as those of all the other exceptional young women who have applied ED. Most people will have a lot of strong aspects (in your case: your AP scores confirmed your GPA, and your 4-year persistence with various clubs activities are positive, leadership or not – not to speak of some of the amazing things you accomplished). Other students might have other particular strengths (such as class rank, or standardized test results).
When a college cannot accommodate >70% of excellent ED applicants just like yourself, there is no way of telling which individual applications might fit particular institutional priorities this year. You have done extremely well for yourself and have a competitive application - and whatever the outcome for everyone, there won’t be any one thing to point to that you could have controlled – it’s likely more a question of the mix of who else happened to apply this year.
Good luck to everyone! All of you are “Barnard material”, but there just isn’t enough “Barnard” for everyone – however, your excellence and achievements thus far are setting you off to a promising college career and future life, no matter where you happen to take classes for the next 4 years.