Good news: you don’t have to! You don’t need to wait until your level is in the 30s to start reading. When you can start reading depends more on your grammar than your WK level.
The Absolute Beginner’s Book Club has furigana so knowing kanji isn’t that much of an issue, though it’s recommended your grammar is about N5 level and knowing some kana words will help. Here’s ChristopherFritz’s guide to joining so you can check for yourself how ready you are.
If that seems a bit too much for you, you can also try the free Tadoku books. They start off really simple, I reckon you could probably read the Level Start books even without knowing much grammar, though I already had a decent grammar basis when I found these so take that with a grain of salt.