I know that my daughter cannot marry a Cohen(she is adopted at the age of sixteen months) she is now 5, should I be discussing her status at age twelve, or should I wait till later. After all, the probability of her being attracted to a cohen when she is of marriagable age is remote. She now goes to an orthodox day school. Should I be consulting my rav, when she is close to twelve years old as to how to go about this?

It's a difficult question to answer without knowing you and your daughter, she should definitely be told she can't marry a Cohen and the sooner the better, but it should be done with great sensitivity and wisdom – not to ruin her self confidence or anything like that, if she is capable to handle the fact maturely – bat mitzvah age sounds right but you must consult a rabbi that knows you both.