Thanks for your insights rx4dsoul and pixiejenna! Im really quite relieved to know that the creases will smoothen out over time....
....but..... yesterday I was a little worried because my bag looked a little bit "hunched back" when standing. First I thought it was due to the soft leather that slouches on the contents of my bag. I didnt mind it at first but when I took the contents out of my bag to waterproof it, I found out that the back part was more than 1cm longer than the front part when folded! So when opened, the back part is more than 2cm longer than the front part, which explained the "hunched back" look of the bag when stuffed.
I compared it to my red cuir and the red one has the same length for the front and back parts, as well as compared it to the nylons. I have emailed Selfridges about it and I hope I do get an answer from them. It's such a shame because the bag is made in France.