How can I reach clients who need CUSTOM web applications? [closed]

I want to offer web application solutions to businesses to help streamline their operations. I want to avoid the now flooded market of e-commerce sites, Wix websites, WordPress sites, etc. My skills aren’t necessary for a website that could be easily created using modern drag-n-drop website creators. The question is, how do I enter that market? The clients who seek more complex web applications are likely going to be big companies or smaller companies with a lot of money. They will be looking for developers with a lot of experience. I have no real-world experience but am confident in the skills I have learned. How can I even gain this real-world experience in the first place? I could certainly find local clients who need simple static websites, but that wouldn’t help me find the clients who need more complex solutions, right? Another factor to consider is that I am 16 years old and will be working by myself. How can I ensure clients take me seriously? I don’t mind offering cheap work at first, but clients will assume that my cheap prices must mean that my services aren’t good.

TL;DR: As a solo, 16-year-old web developer, how can I find clients who need more complex custom web solutions? How can I market myself as someone who offers software solutions for businesses that will actually help streamline business operations—not just static websites. How can I gain the credibility to be taken seriously as such a young developer?