There are several things that you could conclude about Rita. First of all, you can assume that Rita feels bored because she cannot see her friends. We can conclude this because Rita is said to "count the days" until her friends come back from their trips. We can also conclude that Rita is a sociable person as she seems to have more fun when she is able to spend time with other people.
You can conclude that Rita enjoys being active and being around friends and family, so when she didn't have anything to do the rest of the summer she grew bored and lazy, which caused her to count and dwell on the fact that her friends weren't with her and how many days were left until they were.
