I’d say don’t worry about it too much. You seem to be on the right track. Doing 2-3 ECs should be more than enough. If you get involved in more than that you might see it affect your grades, sleep, or social life. Your GPA being a 4.0 is going to be a huge help as well. If you do end up doing well in the SAT then you should be in line to get into your dream uni. Not 100% sure about IVY though