En la flor de la edad/ de la vida

En la flor de la edad/ de la vida
 

En la flor de la edad (when a person is young, healthy, full of energy and ready to develop their full potential)

I found this traslated as "in the flower of one's youth" and "in the bloom of youth". Are they right? Which one is more common and precise?

En la flor de la vida speaks of the whole youth and its potential. I found it translated as "in the prime of life". Is it a 100% match?

'In the prime of (one's) life' is well used and understood, but it doesn't necessarily have to be associated with one's youth. Although that is easily the first thought that comes to mind.
The other two are an exact match for the idea in Spanish. They are correctly translated into English. There's no mistaking that youth (which are young, healthy, full of energy and vitality) is being asserted.

Thank you, Rusty!

I even agree with your descripción of "in the prime of (one's) life" not being strictly about youth to be applied to "en la flor de la vida" too, no matter what RAE has to comment about it. For me, and I'm sure millions of Spanish speakers would agree, "en la flor de la vida" is a two-edge sword. On the one hand it can be used to criticise those youngsters that show a lazy disposition and a brooding character, "¡Por Dios, estás en la flor de la vida! ¡¡Haz algo!!". On the other hand, "en la flor de la vida" also describes those who are no longer spring chickens but still keep it coming, being in the peak of their activity or creativity with no sunset in sight. I'm sure Mick Jagger and Clint Eastwood no longer qualify as being "en la flor de la vida", but not that many years ago, they were!