Piano Learning System

I stopped learning piano and i wish to learn it again ?

I stopped learning the piano when she was 12, I was in Grade 5. I know its stupid for me to quit this degree, but I’m really stressed this time. Now, I’m 15 and I try to play the piano at home after 3 years (do not touch the keyboard at all), but I couldnt. Do you Shaud learn the piano again? If I do, I have to start from scratch or not?