We recommend that they set up multiple groups within that one account. In this scenario, there would be one account creator with one username who is responsible for signing in and logging reading, and multiple groups (of different ages) that belong under that account.
For example, the first group would be for all of the kids that will be in the Early Literacy Challenge, and the default age is 5. The group account creator will set up that group and enroll the group in the available challenge(s). For more information on registering a group, read this article.
Next, the account creator will click the reader profile drop-down to switch readers and select “Add a Group”. Then, the account creator will populate the fields for the second group, and enroll them in the available challenge(s). Repeat as necessary for additional groups managed by one account creator.