Yesterday I sat in an audience of 3,000 people gathered to hear Ellen Johnson-Sirleaf deliver a commencement address. Perhaps not a household name, this extraordinary woman who is Africa's first female head of state, has served as President of Liberia since 2006.

Born in 1938, as part of the so-called "silent generation" she is referred to as The Iron Lady because of her strong will and determination. This grandmother of seven who has been imprisoned and exiled twice is bringing hope and change to her country after 14 years of brutal civil war. The enormous challenges she faces in rebuilding her nation do not daunt her.

In her gentle way, and with a quiet sense of humor, she won the hearts of her audience. She was inspiring. She urged the graduates to go out and change the world.

I think they will.