I got a B+ in a math class that was higher than my grade , but I had A+'s in all my other classes during my first semester freshmen year, will the one B affect my chances of getting into an Ivy League College?
No. If you get rejected with a B+, odds are you would have been rejected with an A+. GPA is but one part of the admissions packet.
It almost certainly won’t. The most selective colleges are looking at more than GPA- they don’t want a campus full of academic drones. They want students with high GPAs (though not necessarily perfect), good test scores, PLUS personal qualities like passion, dedication, drive, involvement in the community, etc.
Thanks for the detailed answer!
Junior year may matter, I doubt one B+ freshman year is going to make any difference, at all.
^^ I agree with the above posters; don’t worry about it.