I manage a sales team for SPX
I operate out of a home office, so I have breakfast with my kids and get them to school. I read and return emails in the morning as I get my caffeine. I research business opportunities, call my sales people, customers, and the home office. Throughout the day I will solve problems for my team and my customers. Half the week I travel the east coast, meeting with new and existing customers.
Take a sales job selling anything for at least one year and a day. It will prove to the person reading your resume that you are serious about it. You can even laugh about how bad it sucked in the interview, but you'll demonstrate that you were determined and nothing was going to get in your way.
Here's the first step for high school students
Take that elective class in public speaking. You may still find it difficult, but it's the first step. You'll be glad you did later.
"You are too young to be considered for that management job."
Even if you're not in your dream job or field at first, pay attention, work hard, maintain a positive attitude, and find enjoyment in whatever the hell it is because it's just a temporary stop on your journey. Your break will come from the person you'd least expect who will vouch for you having all those qualities.
I was the first of six kids and my parents to finish college. Fortunately there was no pressure to meet anyone's pre-determined expectations like "you'll be a doctor like I was". That can be a lot harder.