new-fledged

This is an example of metaphor. The verb fledge, when applied to birds, means both "to grow the plumage necessary for flight" and "to take care of (a young bird) until it is able to fly". So, yes, "new-fledged" when applied to a person should be used metaphorically to mean "someone who has reached a certain (though early) level of maturity". However you may see it loosely used to mean "a beginner".

"New-fledged" sounds a little poetic and old fashioned. "Newly fledged" is an alternative. A fledgling is a bird which has just fledged. A fledgling linguist, doctor, soldier, policeman, sailor, pilot, swimmer, etc would be one who has finished training or learning but is not yet very experienced.

OK, thanks.