When you read the 1st 2nd chapters and move on to the next 3, 4, 5 and so on, then when you come back to the 1 and 2 chapters most likely you would have gaps in memory.
But if your objective is to memorize the whole Koran and you are blessed to do that even before you are born then it would be something else. But you would have to enrol in the Madrasah at a young age and then be taught the way to memorize.
I don't think any Sinkie whether top PSLE or A level student can memorize the whole Koran.
I am not a Muslim but I have no hate in my heart for any religion.
Just a couple of weeks ago I went to a Hindu Temple for a wedding. It felt very peaceful.
I was in Shanghai, China and the good guide brought us to a Buddhist Temple and I saw the people praying, I felt at ease and so welcomed.
I went to the St. Patrick's Cathedral church in New York and again it felt so good.
All lead to God. We should all have an open mind.