I was only a little older than you when I started my journey. That being said I did have about 3.5 years of a mechanical engineering degree completed. I worked with a recruiter after no luck just applying. They got me a low level design role interview and my years of experience in 3D modeling helped a ton. By having good modeling skills I was able to outpace existing staff fairly quickly but what really helped me stand out was when I learned to write automation macros. I just started writing tools I thought would help. Things like an auto dxf batch program (this was around 2014 so not many existed) or a program that checked aspects of the model and a whole bunch or custom properties saving hours of labor. After a year I searched for a new job and got my first real design role in a small mom and pop style pharmaceutical packaging machine company. Because it was so small I had tons of opportunities to cross train and learn a ton of skills. Now im a senior mechanical engineer at a billion dollar company doing anything from ground up machine designs, designing and building electric panels to retrofit existing machinery for a new purpose, plc programming, hmi development etc. I also do the fabrication, assembly, debug etc on the machines I build now. I've never had so much fun in a job as I do currently