I learned piano when I was young, but I never practiced and basically repeated the same lesson over and over. We started taking our 5 year old for piano lessons and I was inspired and wanted to start practicing as well, but I found I couldn't read any sheet music.

I found a course on Udemy: Read Music FAST and Read Music FAST! Part 2. I highly recommend those. It basically took a week or two to get through them and I was able to jump into the author's free Intermediate lesson.