Take Olivia for example, its been extremely popular for the past 10 years and there's many babies and young children called it but it's still a very very old Shakespearean name that has been popular since the 13th century but it's just only recently had a resurgence. If I heard the name Olivia I would assume they were a child even though it's a classic name.
Another name that springs to mind is Emily, i don't think it's roots are as old as Olivia but it has been used since the 1800s it dropped out of the top 100 in 1914 and wasn't heard of for a good 60 years until it re appeared in the top 100 in the late 70s and became the popular name in 90s/2000s, even though the name itself has been around for a long time again I would assume most Emily's are in the age range of around 15-30 years old.
But then again there are some names that are truly timeless like Elizabeth, it has always been in the top 100 and could genuinely be a 60 year old or a baby.
This is just something I was thinking about and wondered what other people's thoughts were?
I'm just curious to hear others opinions on this?