No, how recent an election is isn't the sole criteria. And as we've seen with Brexit, referendums aren't an open-and-shut case for gauging the will of the people. To use another example, there have been multiple referendums in Crimea dating back to the 90s where Crimeans want to secede from Ukraine and join Russia, but I seriously doubt you'll say that the annexation of Crimea by Russia was just Putin doing what the Crimean people wanted to be done since the 90s.
No, how recent an election is isn't the sole criteria. And as we've seen with Brexit, referendums aren't an open-and-shut case for gauging the will of the people. To use another example, there have been multiple referendums in Crimea dating back to the 90s where Crimeans want to secede from Ukraine and join Russia, but I seriously doubt you'll say that the annexation of Crimea by Russia was just Putin doing what the Crimean people wanted to be done since the 90s.