First communion day is very special for children. After a long period of preparation, they will finally receive the Body and Blood of Christ for the first time. There is often a lot happening that day. Your son may find himself sitting in a different place than your family usually sits and doing some things differently than he usually does at mass. He may have a special role to play, such as walking in the entrance procession or helping to bring up the gifts. And he will be aware that he and the other children are receiving special attention that day. Children, just like adults, can get nervous when things are special or different. That’s why the rehearsal is so important. If he knows ahead of time what is going to happen, he will feel comfortable with it and be more able to focus on what is really important during the first communion mass. The catechists and liturgists in your parish have doubtless done their best to schedule the rehearsals at a time convenient for most of the families of first communicants, and it’s important for your son to be there. So find a way to reschedule the drum lesson – or give yourself permission to skip just one – and make sure, for your son’s sake, that you attend the rehearsal.