Hi , is end March good for travelling in Xiamen especially with a 96 years old lady on wheelchair ?

I think so. It would be fine and sometimes cloudy then, with the average temperature of 20-22C. You will feel it not too hot and not too cool. Thus it is a nice travel season, especially for the elderly. Anyway, you may also meet rainy days. If possible, it would just rain a little and would not bother your travel.