Grace, Helen, and Mary*

Grace, Helen, and Mary were discussing their ages one day, and in the course of their conversation they made the following statements:

Grace: 
I am twenty-two. 
I am two years younger than Helen. 
I am a year older than Mary.

Helen: 
I am not the youngest. 
Mary and I are three years apart. 
Mary is twenty-five.

Mary: 
I am younger than Grace. 
Grace is twenty-three. 
Helen is three years older than Grace.

It is of course too much to expect that three young women should be entirely truthful when speaking of their ages, and in the present instance only two of the three statements made by each girl are true.

How old are they? 

Help needed, I can't figure it. Thanks.
Lue A. S.

* This puzzle is a clever variation of puzzles about ages...