Was it sheer luck that I passed my test?

In December I took an important state level test that can lead me towards a prestigious job. Very few people pass it every year. The test was conducted on computer and it was multiple choice based. Many of my peers took this test as well. Although I was quite prepared, the question paper did seem pretty complex and I had lost hope. However, I first answered all that I knew and then attempted the ones I had doubt about or didn't know (there wasn't any negative marking). In the end I started having doubts about one answer I had randomly chosen and I decided to change it. My mouse froze and although I tried my best it didn't do anything. The timer ran out and the screen was closed then. Coming out of the examination room I realised that I had indeed selected the right answer.

Now, every year certain number of people pass this exam and thus the highest scorers that fit into these certain number of vacancies are selected as successful candidates. The results came out recently and I saw that I have passed and that I'm the only one of my peers to pass it. However, here's the trick. I could have failed it if I had given one more wrong answer. What if my mouse worked and I had changed it?

I do feel little bit of an imposter but I know I had worked for it. However, I really want to know if someone else has had a similar experience.

Was it sheer luck that I passed my test?
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