I think the best way to help your sister is to talk to your mom . Let your mom know your concerns . It may be helpful to share your experiences of high school or ask your mom what her experiences were , and ask her what she thinks your sister may need to be prepared for . Ask your mom , how can you play a role in helping your sister be prepared ? This can be a tricky conversation as you don ' t want your mom to feel her parenting is being undermined , questioned or attacked . This isn ' t the type of thing that can change or be fixed immediately so I think just gently expressing your concerns at first will open up a line of communication . And hopefully keep your mom more open to maybe allowing your sister to have a part time job or volunteering or taking a summer course at a community college . Good luck !