If you do decide to apply to the States, you are at the very beginning of a long application road.
Your grades are good - top 1% is excellent - so no worries there. Keep up the good work.
Whether you need practical experience or not depends entirely on the programme you are applying to. It wouldn't hurt to substantiate your academic achievements with some professional experience.
Now, as for the Ivy League, do some research on schools you would like to study at. Many fantastic business schools are not in the 'Ivy League'. The 'Ivy League' also includes some schools where, at a closer look, you would not want to be at. You need to spend lots of time on the websites of those schools, looking through admissions requirements, programme overviews and faculty lists.
The very best to you for the next year!