I've started to work as a software developer when I was 16. My first job was a small programming job as a casual employee (20h/month) for a research institution (publicly funded) - it was for minimum wage and I hated it.
After 4-5 months, I've decided to become a freelancer and searched for contract work. I've never used Fiverr or other platforms and I'm convinced that neither should you, because this work will only lead you down the wage path where no one really values what you do.
Try to find small local software companies in the range 1-30 employees, go to local meet-ups for software developers (or even organize your own ones) and get to know those people who can give you a job. I'm currently 19yo and I'm meeting executives at my local chamber of commerce. It's not that hard. But first, you have to lose the attitude described in this sentence:
> software companies are not willing to hire people my age for good reason
This is simply not true. Maybe there are some, but not all. I've get paid the same amount of money as other freelance senior developers. They don't care about my age. They just care that
- I can what I say
- I can do what they need (I'm doing web applications & app development)
- I do it professionally and communicate properly
Just go out, drink coffee with other software developers, tell them that you would love to have a meeting with their executives and you're ready to go.
Be confident in your skills (but never ever make the mistake of overestimating yourself), be calm, show your expertise and that you can and will do the job.
Connect with people, this is the most important part for freelancing work - every time you go out and eat something, go with some project managers who happen to be there, too.
Maybe this sounds too easy to be true, but this is what I did. And I'm sure you can do it, too.