Should I start a blog about front end web development, Japanese, or not start a blog at all?

I'm a community college student about to transfer to a university in the Fall of 2019. After college I'd like to work as a web developer because I like programming and I need a full time job with benefits. However, web development is not my dream job. My dream job is to build an app that teaches the Japanese language and make it my primary source of income. This is my dream job because I love studying the Japanese language. I read an article from the blog Classy Girl Career that said people should write blogs to help them obtain their dream job. The author said that she received job offers from writing her blog. So I’m really at a crossroads because I really need a fulltime job immediately after college, but I don’t think I can write about front end development because I’m not passionate about it. It’s a means to an end for me. I could write a blog teaching the Japanese language but I think I would derive more pleasure from the act of studying it than writing a blog about it. I want to build an app teaching Japanese for a living but at the moment I’m unable to do that because neither my development skills nor my Japanese skills are high enough for that yet. I’d like to start this business after I’ve worked as a developer for five years and my Japanese skills are up to par. What should I do?