You can probably do a fine job, if you try to be humble, diligent (practice etc) and take things just one step at a time. Enjoy learning and growing.

• The main rule is "follow the conductor", playing one hand or one note if necessary. Take steps from there and don't give up.
• Some music directors really are uncomfortable directing and prefer to follow you. In that case do your best--you can be very helpful sometimes.
• (I am using the terms "conductor" and "director" interchangeably. "Chorister" is commonly used for those but historically really means "choir member".)