If you have availability into the evenings and weekends, let the interviewer know. It's always helpful to give them an idea of your schedule and any extra times that you might be able to assist. If you feel pressured to work times you know you're not available, be careful not to say "yes." It's always important to only taken on what you know you can do. If you change your mind or if your schedule opens up, you can always add more shifts. If you're interested in assisting with taking the volleyball team to tournaments or driving the second grade class to the zoo, let them know.