I started to learn software development at 37 years old (shoutout to freeCodeCamp.org!). That was in 2017. I went the frontend route, so I naturally started with html, css, and javascript. Then, since React was already the most popular framework then, I started to learn it and build projects solely on React. I skipped Jquery, pre-ES5 javascript, and things like that. I focused on what was fashionable.
It turned out great for me! I am a very happy and successful (in financial terms compared to what I earned early or expected to earn these days) web developer.
Funny enough, my first job was using Ember. But six months in, the company decided to migrate to React, since it was getting harder and harder to hire people that wanted to work with Ember. Then a couple of React jobs. And now I started a job using Vue. So still learning fashionable things.
Btw, I never noticed ageism against me. I worked on a big Brazilian startup and then on three small American startups. Of course, plenty of the jobs that I applied for and didn't get could be because of ageism, I'll never know, but I consider myself to be successful in getting jobs, so at least I think it is not something that affected the general outcome of my career.