Answer:
When young, I am sweet in the sun. When middle-aged, I make you gay. When old, I am valued more than ever.
Though easy to spot, when allowed to plume, It is hard to see, when held in a room.
I can travel from there to here by disappearing, and here to there by reappearing.
Iβm a word, six letters longΝΎ I sometimes enter with a gong. All in order from A to Z, I start with the letter B. What is the word?
I turn around once. What is out will not get in. I turn around again. What is in will not get out.
What is so fragile that saying its name breaks it?