How long could it take for my nose to reach its final shape after a rhinoplasty?

Because you are still very early on in the recovery process, you shouldn't be concerned with the final results of your procedure just yet. In many cases, it may take an entire year to see optimal results following your rhinoplasty and up to two years for patients with thicker skin who underwent a complex procedure. Unless you are having a problem with functionality, it's best to continue to be patient during the healing process.

     The tip at 4 weeks will rotate up after cephalic trim in a closed rhinoplasty (seen it a hundred times or more). 

Healing from rhinoplasty has several phases. The early phase is the swelling and bruising in the first week. During the next couple of weeks the swelling begins to go down and you can see the general shape and proportions of the nose. By three months most of the swelling has resolved above the tip. The tip will look much better but still lack definition. The definition of the tip can then take up to a year to be fully realized. I would not expect your tip to "rise" by itself two months after surgery.