A. Colleges do not care about Middle School grades,
B. Nobody was ever rejected for having a A-
C. You are in 8th grade, for heaven’s sake! Focus on how you are going to get the most out of high school as you can, NOT about Ivy League Colleges. You should be focused on how you are going to change the world, not on at which college you will spend four of the 80 years that you will live.
Change the world = great life goal
Change the lives of people around you = great life goal
Test the limits of your abilities = great life goal
Be a physician, a scientists, a lawyer = great life goal
Be a carpenter, electrician, welder = great life goals
Be a performing or creative artist = great life goals
Lead a fulfilling life as a spouse, parent, and friend = great life goal
Attending an Ivy League University = not a great life goal.
The college that you should attend is one which is the best fit for you, while helping you fulfill your life goals. There are a few hundred colleges out there, and at least three dozen will fit that description, and few, if any, of them will be Ivies.
Base your college selection on what you learn about yourself in high school and what you want to do after high school. Do not base your four years of high school on some vague imagined idea of a specific college or set of colleges.