What exactly is a success? Money? Fame? Career? Peace of mind?
When someone says 'oh you are so successful', what does it really mean? Can't success mean different things for every individual? What someone defines as our success can very well be reflecting their own aspiration and/or dream. For you, it might not mean as much as it would to the spectator of your life. So when someone says 'you are successful' it is their perception of our life and its stages.
When someone has reached a high-level position at work A might say that that someone is so successful but B might think that that someone is compromising on his health, family and mental peace which B has the luxury for, so he perceives that he might not be at a high-level position but he is more successful than that someone. I think you get the gist.
And when one asks themselves 'am I successful?', would the answer ever be a 'yes'? If we are truly on the quest to be our best, then would we ever label any stage of our life as 'success'? I have come to believe that success is a mirage, an illusion which doesn't actually exist.