A: In many congregations, there is a set custom about when a bar or bat mitzvah can be celebrated. In my own congregation, the bar/bat mitzvah reads three aliyahs on Friday night, as a kind of "practice run" in front of live people, and then reads 7 aliyahs and the maftir on Shabbat morning. The rabbi of the synagogue usually is the person who determines the timing and date of a bar/bat mitzvah. If this question reflects a personal concern, I suggest that you speak to your rabbi directly.