Some corrections, suggestions. According to what I remember, I didn't do well on tests throughout my school days. I'm ashamed to say it, but I flunked the tests of the every class which was a mandatory subject when I was little. From what I remember, I didn't do well on tests at school. I'm ashamed to say it, but I flunked the tests of the every mandatory class when I was young.

As I remember, in my school days I didn’t do well on tests. I’m ashamed to admit it, but when I was little, the only test I used to pass was the (name of the mandatory subject: mathematics, science, etc) one.

could you explain more what your question is?