Here is an interesting short summary: http://www.ncbi.nlm.nih.gov/pubmed/20638774. Basically, posture work was more effective than kegals in dealing with stress incontinence.
He works with back pain patients, but his exercise regimens basically address postural issues. A posterior tilt to the pelvis will contribute to stress incontinence and other problems. Anyway, to make a long story really short, muscle imbalances need to be fixed in order to be able to maintain good posture.
This then leads to:
Her exercises help in learning how to maintain good posture throughout the day.
Both books are available on Amazon.co.uk.
A significant number of young women in their twenties deal with some degree of stress incontinence, so you are really never too young.