First ever 'A' grade at US

My end term started last week, 2 exams from my 3 subjects already ended. One to go. I'm pleased with my performance at the Math 5358. Its good to have, 'A' grade for first ever exam at USA. Here exam results are extremely difficulty to obtain not like in Sri Lanka. The grading is so stupid, I don't know why. We need to get 91 to obtain A grade and 81 to obtain B grade. Nothing in between A and B. But when I was there at University of Peradeniya, we had lots of grading stars at A+ to F.......A+, A, B+, B, B-, C+, C. And also its not a problem to get A for a subject. If we can stay at the top of the class or at least top 5 or 6 then there is no problem with getting A+ for it. The bell curve will decide who gets A+ and who gets F. At least lots of people will get B+ which is 3.3 in the GPA points. Here the same GPA points for A , which is 4.0 and B 3.0. This makes kind of a hard to stay at least at 3.0 margin. Hope my A grade will do help for it. B'se I'm not sure about my other 2 exams. The final grades are yet to release. One good thing is, now I know how to tackle this system. My target is next Fall semester. A's for all the subjects and 4.0 GPA. We'll see. Hurrah for my First Ever 'A' at Texas State University.