i like to play piano.but my fingers are short so it’s hard for me to play octave.i dont take classes and how can i play octave very well without pressing the wrong key?
thanks alot..and thank you for making me realise that i had put my Q in the wrong category 
…
again..thank you very muchh <33
First of all, you may want to put your question into the accurate category, not "Theater"… that might get you some more answers! =)
Second, I would practice playing octaves over and over. You CAN actually manage to stretch your hand out and it will eventually be easier. I have really small hands too, so I feel for you! It took me a while to be comfortable with jumping around a lot without looking down to see if I was playing the correct notes!
If you really just can NOT stretch your hand to an octave’s width, don’t be afraid to press down the pedal, play the first note then quickly move your hand only SLIGHTLY and press the upper note with your pinky finger. I can’t describe it very well… It sounds a little funky but it will mimic the sound of an octave. It will sound slightly different though, and it can take a lot of practice to make it sound right.
This is just what I have done, but be aware that I don’t take lessons anymore, I teach myself! So I’m not sure if this advice is technically right… sorry! xD