I’ll second what Omun said; with a rough idea of your grammar and vocab level, pick something to try and just try it. I read my first graded reader a couple months ago with a higher-level friend to help with grammar points I didn’t know and jisho open for the vocab we had to look up. I was about level 12 and only a couple chapters into Genki. It took us an hour to read through a ten page story, but it felt really good to do that. I’ve since gotten better with my grammar and it’s a lot easier to read through the same stories on my own, now, but my WK level hasn’t really changed much, since the vocab I’ve learned here since doesn’t really show up in the stories I have.
If you’re interested in graded readers or parallel texts specifically and would like to talk to others who own or have read them, you might also want to check out this thread. You can ask questions about the books you’re looking at or find some resources to free or cheap stories that you can try out without committing to a whole graded reader.
Just jumping in and trying it is probably the best thing to do, though, especially if it’s something you’re excited to do.