The number one factor for college admissions will be your academics…grades and rigor.
I echo the posters who have said do what appeals to you in terms of your ECs. If starting a DECA chapter is appealing, do it (your school doesn’t already have one?). If playing tennis is appealing, do it (are you playing this season?)
As far as starting a non-profit goes…are you sure there isn’t a similar non-profit that already exists that you could start volunteering for? You aren’t going to get more college admission ‘points’ by starting a non-profit. None of the ECs on your list will be a hook.
I wouldn’t necessarily be thinking about a college list right now. Ultimately you will be looking for a college that fits you well. Reaches are easy to find, but spend time finding more attainable schools that fit and are affordable. You will also need to speak with your parents about what your budget for college is, this is critical to building a good list.
When you get to the point of list building/researching, you will find out that not all 8 Ivy league schools will fit you. How could they when some of the schools are so very different, aside from being in the same athletic conference? Most Ivy league schools don’t have a finance major either.
Continue doing well in HS and make sure to enjoy it as much as possible. Good luck.