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.