Even the most confident P7 may be a wee bit worried about starting secondary school. As schools have been closed, they won’t have had the things like induction days that they normally would. Just reassure them that everybody starting school has been through the same situation.
There’s no point pretending that primary and secondary schools aren’t different. But there’s no need for them to be scared. There are plenty of practical things you can do to help smooth the transition and ease any worries they have.