I was 23 once, dreaming of adventures. I envy you, and happy to offer a few suggestions. Before you send for a passport , (you seem to have time ) there are two things you should do. First get a notebook and write down any question you can judge as useful. Then go to Students Services at your College, tell them about your plans and ask them if they can help you to some extent. They usually have some documentation about your passport question, travel agencies that offer student discount, maybe you'll discover a section in the library you never browse. Your local library certainly has good informations in the Travel section.I would also write to the Japanese Embassy in Washington, requesting informations.
Being a mom and a GM, i certainly be worried if my daughter tells me she going to some place in the world I do not know. By being organized, you're gone to calm her down. Leave the informations, where she can consult them herself. Keep the questions to yourself, talk only about what you are sure of.If she feels the need to check, at least she'll understand that you speak about something you know . If I can be of further help, PM me, I worked in a Travel Agency for a while and left a lot of details.