Question
Does a non-married male have to wear a Tallit?
Answer
The custom of all Sephardim all Yemenites and many Ashkenazim is that a boy starts wearing a Talit Gadol at least from his Bar-Mitzvah, many start at a younger age for Chinuch, some Ashkenazim mainly in Poland and Lithuania have the custom that a Boy Does not wear a Talit Gadol until after marriage, the right thing for one to do, is to follow his families tradition.
[המנהגים מפורטים קצת בפסקי תשובות על המ"ב סימן ח ס"ק ד אות י]
