Education in the US: are we falling behind?

I myself don't know any statistics on education differences between U.S.A. and other countries. But I do know that the U.S. economy is doing way better than the economies of many, many other countries, so we must be doing something right. I also got the chance to attend school in Ukraine for almost four years so I can use that experience to reflect upon a little. What I remember was that I started out first grade (which in Ukraine you start at seven years old) by making very good grades, all A's I think. As I went up in grade levels the material became harder and gradually my grades declined. The teachers were very strict, I remember being terrified of being called on by the teacher every day because I knew that I couldn't give a perfect answer. I would sit with my mom behind my desk at home and have her try and tutor me in math for hours and hours before I could go outside and play. When I mentioned that my grades declined I didn't mean that they were bad, I meant that they weren't all A's anymore so I was still OK, it was just getting difficult. Also, in Ukraine everyone skips the forth grade (I have no idea what the reasoning behind this rule is) and jumps right into fifth. So the school is divided into two parts, grades 1-3 with all the little kids and grades 5-11 with all the older kids. Once I started the "older kids school" that's when it really became very difficult and it was also the first time I received C's on my report card. Fortunately, I did not finish fifth grade in Ukraine because I moved to America that spring and jumped into 6th grade the following fall. Throughout my middle school career I got mostly A's and it was a breeze, in high school I had a GPA of 3.2, and honestly I didn't even really try because I knew I could get good enough grades by just doing the minimum. So yes I think that maybe we are falling behind in education but so far we are still ahead of other countries in many aspects so I don't think it should be considered something of immediate concern.