I had a similar dilemma many years ago, taking the IB program at my school and ending up being very challenged by it. It is only a trick of our imagination to think that everyone else in class is having an easier time. Talk to your teachers and trusted classmates, point them to this wonderful post you’ve written, remember that you are not alone and there is nothing to be terrified of — except of potentially losing sight of what makes you a happy and curious young person.
Try to offset the weight of your decision (I know something a little bit about family pressure in your culture) by focusing on the experience of learning. Whether in Hannan, Osak or Hansen, Wisconsin, life’s greatest privilege is growing and discovering new worlds: no matter what circumstances you find yourself in. I have a feeling you’ll do great either way!