@neda1004 your observation seems about right. I've got two hints for you:
You can replace knots between two strings of the same colour with bf at the left edge and fb on the right edge. This should help you keep it a little straighter.
When you are tying, make sure you aren't pulling to the left as much. Make sure that the bracelet is secured well close to where you are tying and not all the way on the top. If it is only secured at the top, it will move around a lot and get wonky.
hi there! i tried this pattern and note that it isn't my first time making friendship bracelets, but this one turned all wonky and crooked. if you look at the pattern closely u can see on each side all the knots are backward and i believe it's making the bracelet to twist to the left.