If I were you, I would put the native reading materials on hold for a moment.
Instead, it would be really great to work on your foundation. It is really important to have a strong basic understanding of Japanese before moving on to more difficult materials. The reason why is because too much too soon can lead to some bad habits, mistakes, and even burnout. I understand wanting to know Japanese immediately if not sooner, but there is a lot of careful work that should be done to assure your success in the long run.
I think it would be better to start off small with basic grammar and vocab before jumping into the JLPT studies as well. Maybe a resource like "Erin's Challenge! I Can Speak Japanese." Contents Library | The Japan Foundation (Erin’s Challenge) could be helpful to you. They have the scripts, you can follow along with and check before hand so you don’t feel overwhelmed or lost. It’s also free, which is a bonus.
Another thing would be to either use a textbook like genki or minna no nihongo if you prefer textbooks, or to find an app that allows you to view grammar in use rather than just a separate piece. I like bunpro, but there are tons of apps and materials available out there. Also, building up vocabulary is a very good idea. There are also a lot of apps and books available that allow you to see the word in use. (context is helps with remembering). Or, at the very least, when you come across a new vocabulary word, look it up on a website like Jisho.org and click on the sentence tab to read some examples using that word. Of course, these will have sometimes very complicated sentences. Don’t get discouraged!
I am all about reading! I really agree that reading a lot is the best way to learn a language. There is really no shame in picking up a children’s book and starting there. I did that. I went to the children’s section in the library and started with grade one and just tried to remain consistent. When starting to read for the first time, it is hard to know if the level is too high for you. I would recommend looking at the first page and trying to read it. If there are more than 3 words you don’t know, I might consider reading an easier book. Another good thing is to not focus on every little vocabulary you come across, but to try to gain an understanding from the surrounding sentence. And, if a word shows up more than 5 times, it is probably used throughout the entire book and looking it up could be very beneficial.
Of course, it is up to you to find a learning style that works best for you! I think you can definitely do it. You seem very serious about studying I am rooting for you! Good luck.