There is actually no right time for anything in life.
"Right time" is subjective depending on what you want...you know why
Let me tell you a story
Three blind men who wants to experience an elephant with one placed on its back, the other holding on its truck and another rubbing on the belly of the elephant,
They would all have different experience based on where they were placed.
The moral of the story which connects your question is this
There are many time to sell but there is no right way even if given expert advice.
You have to pick and choose according to your own need.