when i was 2 years old my sister was half in my age now i am 100 years old then how old is my sister?

When I was 2 years old, my sister was 1/2 my age ==> she was 1 ==> she will always be 1 year younger than I am, and she will never be able to catch up to me. Now I am 100, so my sister must be 99 .