Hi, I successfully transitioned from a non-CS background to a backend developer at the age of 36.
I originally worked in marketing for about 8 years. During the COVID-19 period, I started learning Python as a hobby, found it enjoyable, and completed a 6-month bootcamp. After finishing the bootcamp, I applied to over 100 companies over about 4 months and eventually got accepted by 2.
What helped the most was uploading a side project I built (a simple shopping mall backend) to GitHub and detailing my actual troubleshooting experiences in my applications. During interviews, I was able to answer questions like "Why did you use this technology?" based on my own experience, which was a big plus.
To all the non-CS majors out there, don't hesitate because of your age. I believe that if you don't give up, a path will open up. Feel free to leave a comment if you have any questions.