Normalizing student grades against median

You are given a dataframe containing student information, named df (shown below). Suppose you want to normalize each student's grade based on the group's median age.

Age	Favorite Color	Grade	Name
20	blue	88	Willard Morris
19	blue	95	Al Jennings
22	yellow	92	Omar Mullins
21	green	70	Spencer McDaniel

Write a function using Python (Pandas) that will add a new column to your dataframe containing a new grade normalized against the median age of the students.