Failure in life is when someone passes through life without having a clue about why he/she was created.
When you attempt something/project and it doesn’t work out, I don’t see that as Failure from a broader view…at least you tried to figure out how things would work.
I would say that a person has failed when he leaves this world without knowing why he/she was here in the first place.
It is therefore important that you constantly engage with God, your Creator, in order to get revelation about the purpose of your existence. Life is short…Live on Purpose.

Note: It doesn’t matter how old you are now; God called Samuel at early years (some say about 11 years, whereas Moses had his encounter at about 80 years. David fought his giant at 17 right? Caleb went after his giants at 85 years. Therefore don’t settle, nothing is too late. God bless us!