My nose tip is very round. Is there any way that I can change my shape without surgery?

Nonsurgical rhinoplasty is an excellent option for dorsal augmentation in a temporary fashion.  Also in patients with medium to thin skin, it is possible to have a moderate degree of refinement created in the tip of the nose.  However, for patients with very thick skin, the result will be very limited as the filler will not be thick enough to show definition through the skin.  

To make any changes in the shape of the nose requires a rhinoplasty procedure to shape and alter the cartilaginous and bony framework that is present. Thick skin will be a bit of an impediment to seeing a very refined result the tip of the nose. Computer imaging would also be helpful to understand what can and cannot recall what with the rhinoplasty procedure. For many examples and more information, please see the link below 

Since you are underage, you need to confer with your parents before altering your appearance. In general, by sixteen years of age your nose should be done growing. Non surgical procedures such as fillers are very helpful to improve the shape and contour of your nose. From the images you provided, it seems like you would be a candidate for a surgical open rhinoplasty which generally starts at a price of $7,800. A consultation (and if you are under age, parental consent) is always necessary to give you definitive recommendations on how to improve the contour of your nose.