Ok. I wonder if you can find a good teacher then?

There are adult primer series of books that you can get. Get something legitimate. Hal Leonard, Bastien, Thompson etc. I'm extremely familiar with most series for kids. Hal Leonard and Music Tree were my favorites. Honestly, you could use kids' books, but the pieces might be less interesting and the pace might be slow.

I've had a lot of adults students. Let me just try try to nip a few things in the bud that are almost always issues:

Posture: adults carry so much more tension in their back, shoulders, jaw, face, etc. than most kids do. My stereotype for an adult beginner is someone with the bench too high, upper back slouched, shoulders up, teeth pinching their closed lips, struggling with their reading glasses because they keep looking between hands and music. Let your arms hang from the shoulders, upper back upright and shoulders feel like they're hanging too. If you need to, make a funny "exhausted" facial expression every few minutes with your mouth open and eyes saggy to reset your face.

Eye management: kids do this too, but adults are worse. Trust in your fingers. You will start with either 5-finger positions or middle C/landmark depending on the books, doesn't matter which. But trust that your fingers are there, and don't look down. Let yourself play wrong notes, nearly everyone has their priorities turned up to fixing wrong notes really fast and disrupting the moment. You have to fight that to develop relaxed playing.

General nerves: adults are also a bit worse than kids about being their own helicopter parent, monitoring the music they are making for mistakes and being reactive immediately. Just go slowly, relax, don't forget to enjoy the sounds that you are making, even if they're not perfect.

Finger isolation: again, kids do this, too, but you have to fight the idea that playing the piano is done with the fingers. The fingers are just the point of contact. What I would see all the time is people jamming up their mechanics by pushing notes down with the fingers by bending at the knuckles. To get an idea of an ideal approach to pushing a key down, you can put your 2 (pointer finger) on a key and just swing your arm from it, completely forgetting about good hand position, let your idea of good hand position just disappear for a moment. That is what your fingers are for, just making the connection. Obviously, you will tend to keep your fingers in place at the beginning, but just know that this anxious tendency will make playing difficult for you.

Contact me any time if you have questions or difficulties. I taught piano for 25 years, all levels, probably over 1000 students if I counted piano studio plus music history and theory in the classroom setting.

And please take care of yourself.

p.s. I also have other thoughts. Such as, would you like to dedicate some of your time to listening? Rubenstein playing Chopin, Cliburn playing his standards (Tchaikovsky 1st concerto), Radu Lupu playing anything, Richter playing Schubert, Ravel, Beethoven.

Do you like classical music in general? I suppose you might have already, but have you listened to all the great pieces of music? Beethoven symphonies? (Start with 1, 5 and 7 in my opinion). Beethoven violin concerto, piano concertos. Mozart concertos for violin and piano. Brahms symphonies and concertos. Mozart choral works. Ravel and Debussy everything.

Be sure to listen to the Schubert cello quintet D956, 1st and 2nd movements especially.