Alejandro’s response I agree with wholeheartedly! He made so many fantastic recommendations for the path you want to pursue.
I would also suggest as a high school student to find a part-time job at a local boutique or larger retail store I did this in high school and learned a lot about the fashion industry and how things work in the retail environment by observing and asking questions. The best part for me was meeting customers and helping them.
A huge part of anything is networking and making contacts. People like to help and share their advice and expertise. With social media, specifically Instagram, you can make so many connections and once you follow someone who inspires you, send them a DM and introduce yourself and ask a question. That will start the conversation.
Hope this helps! Wishing you good luck!!
Have you considered looking into buyer internships? A buyer is someone who buys clothing for a brand. let's say... Zumies is looking to buy some new clothes or products. A buyer goes out and meets with suppliers and studies the product quality, the style, and analyze whether or not it fits the style of the overall brand.
Buyers are a great way to learn about style and how to work within a brand that could really help you as you become a stylist in the future. Because you live in SF, a major city, I'm sure you could look into the corporate end of some of your favorite brands and see if they have SF location and high school internship programs you can get into.
This could be a great first step! Secondly (and I always suggest this) finding a style mentor to help you become a stylist would be a huge help to learn trade secrets on how to get into the industry. Try asking around to see if any of your friends parents are stylist or if the work for a brand or company that might have buyers. From there, search through their networks to see if anyone of interest would talk to you! Work on building these relationships early on will help people feel invested in you and ultimately will help your relationships as mentor >< mentee in the future.
You definitely should start with a part time job at a retailer that you love. A good way to get practice coordinating clothes is through visual merchandising. A visual merchandiser styles the mannequins and coordinates how products will be displayed. I got my start at Forever 21, first as a sales associate and became a visual merchandising assistant, and made my way to corporate as an ecom assistant stylist. Show interest with the visual team at the retailer you work at. If you want to do more freelance stuff, you first want to build a portfolio of work, so you will need to coordinate some shoots. You can ask up and coming photographers, models, hair stylist, and MUA to work for trade. I used to find jobs on Craigslist and I would find the team on Model Mayhem. Not sure how well those sites are doing now!
I hope that helped!