I am a 15 year old girl and well over 2 inches shorter than my mum. Any way I can grow taller?

From age 15 to 20 expect to gain about 10 lbs and increase height (stature) 1/4 to 1/2 inch.

That is, at age 15 you are very close,to your adult height but you are still adding weight.

Reference: http://www.cdc.gov/growthcharts/data/set1clinical/cj41l022.pdf