How much taller do you construe my sister will grow?

She just turned 12 (Dec. 4), she's 5'1", she have not gotten her period all the same. Her dad is 5'9", her mom is 5'5", she has a efficient metabolism (if that changes anything), beside that information could you predict her adult rise? she want's to know...thanks! I contemplate she's going to be about 5'6
http://www.webmd.com/content/tools/1/cal...
dance there and permeate in the info you might win a better answer there
most girls will grow to be taller than their mum. so if i have to guess, not knowing any other history, i'd say 5'6".