Is automotive mechanic a good career job?

Yes. Firstly, it's a trade that requires a tremendous amount of know-how and keeping up with technology. In the US, it's hard to imagine a society without cars. The latest trend of using Artificial Intelligence, specifically Machine Learning and, later, Deep Learning, will still require technicians to repair autonomous vehicles. In other words, there is job security. Secondly, the consumer is very aware of which businesses employ mechanics with skill as opposed to those that don't. Thirdly, for someone who is mechanically inclined and drawn to engineering and machines, the technology involved with cars spans quite a range. I predict that, while diagnostics will become more and more mechanized and automatic, the cars themselves will become far more complicated, simply because the automotive industry thrives on repeat sales and to do that, and ever-increasing feature set and intricate design will become necessary, and mechanics will become even more valuable. Especially mechanics who can continue to learn.