Let’s understand this by an example. There was a father who wanted his son to win an olympic 100m race. The boy was 100kg in weight and never ran a race. The father went to the coach and asked the boy to be trained for olympics. He also asked how much time would it take for a boy to win an olympics race. The coach answered, he can provide the best training to the boy but there is no guarantee that the boy will win an olympic race. However, he said if the boy comes for training everyday and works hard he will definitely improve his running speed. The point is, it is difficult to predict how much time it may take for the site to get rank #1 in SEO. If the site is new and the keyword is competitive, then it may take 12-24 months to rank. However, if the keyword is of low competition, then it may rank in 3-4 months. It completely depends on the current rank status of that particular keyword and keyword difficulty.