I think that’s great that you are thinking a long term project so early on in your photographic journey! At 48, even I am a bit overwhelmed by the scope of your project. There will just so many points in your life where you are going to gain wisdom, see changes, and let things go. Sometimes you won’t even realize an event or decision was important until years later. My suggestion would be to break your topic down and focus on smaller “sub projects”, which, over time will reflect the over all theme you are looking for. I’m no expert and I kind of feel ridiculous offering advice but from a middle aged guy to a high school student, you many want to try these mini projects:
1) Find subjects that you believe won’t exist when YOUR kids are in high school (and, if possible, the way people interact with these soon-to-be-dinosaurs). Telephone land-lines? Taxis? Old buildings in neighbourhoods where gentrification is going on? Current trends or fashions?
2) Shoot people and things that YOU care about and interest YOU most. Not what you think others would be interested in. Think of it as a time capsule to your future self: this is what I loved when I was 17.
3) Shoot old people. This is a project you can really sink your teeth into. Start with grand parents and others in your family. Ask for some time to do a photo shoot of them in their home or while they are engaged in their favourite pastimes. As you shoot, ask them about their high school years, their careers, the things they are most proud of. Try to shoot portrates incorporating objects that reflect important things in their life. Gramma showing off her medals from desert storm. Grampa holding a photo of your mom when she was a little girl. Ask tons of questions. Get them talking and listen carefully. And then leave the door open to come back and do another photo shoot on another visit. I bet they are going to love the chance to share and spend some time with you.
You can move on to other people, like the neighbour across the street. A teacher who will be retiring next year, etc. Get their stories and try to capture them.
If if you can do this, you won’t just have some great pictures, but you’ll learn a lot about your subjects and strengthen your relationships, which will impact your own journey of maturity. And years later, you will have some photos you will truly cherish.
Reading all this, I think, who the heck am I to be giving advice? Take what you want from this. All I can tell you is what I wish I had taken pictures of when I was your age. It would be wonderful to see what other old fogies like me think about this project.
All the best luck in your photographic journey.