Math Shock in graduate program

Even though you had a disadvantage at your home country, if you are in graduate school at USA, it means you passed many filters (scholarship, admission exams, undergraduate grades, peer competition).

Definitely you will struggle more in the beginning, but you have what you need to succeed. It will take more effort and will.

Just remember where you were a few years ago and how you dreamed to be where you are. Now you are there and perhaps you just need to believe you are there. You need to feel you deserve it, go for it.

It will be hard, but eventually it will get easier and you will enjoy it.

Congrats, wish you success.

Sometimes, particularly in maths, feeling that you are a slow learner can be a good thing.

Some people demand of themselves that they attain a much deeper degree of mastery of a subject, than others do. While another person may be satisfied that they can apply the methods taught to them, others are only satisfied when they can apply the methods as taught, visualise how the methods work, relate them to all surrounding things, fully understand the boundaries in which those methods apply, explore all avenues and have a clear picture of the full gamut of innovative and unexpected ways they might also be used.

These people have to work much harder to be satisfied with their understanding, and they may feel they are finding it more difficult than others to learn. In reality, they are simply setting the bar higher for themselves.

The classic example is Einstein who was famously slow to learn maths. But it turned out that his mastery of what he learnt was simply deeper.