You might not believe this... alot of people refuse to believe this, unfortunately they are no longer here to argue with me.... but you need A TEACHER

Also, just when you decide to quit piano, GET A TEACHER

Not any teacher, you can find teachers who have been playing for decades, BUT you are not impressed by what they have to offer. no, I am not saying these are bad teachers, merely they are not suitable for you. so next criteria is a Suitable teacher.
How do you know you have a suitable teacher ? easy, let her play a piece, any piece... Happy Birthday song, or Twinkle-twinkle little star will do just fine.. forget Chopin etudes, Beethoven's sonatas what have you.. Are impressed with her rendition of 'Mary had a little lamb' ? Can you reproduce the same sound ? You think you can , try it !

Can she teach you to reproduce the same sound.. In case ppl miss the point, my 5 years old son can play Happy Birthday.. so notes and rhythm wise is trivial. To really appreciate piano techniques, get a real pianist to play the same song for you.. no , not recordings of Rachmaninov, or Argerich, Pollini what have you.. you need to hear life performance.
Also dont forget that piano takes decades to master. Sure you can learn Fur Elise in one week without prior piano lessons... but in case you think got it right, get a real pianist to play it for you.. If you can hear the difference and appreciate it, piano is the right instrument for you. If you think you can play as good as her, you should consider an accordian.