If you like the A5, there you go. See if she likes them too. If she does buy her a nice original. Stay away from the new guns sold and labeled as an Auto-5. They might be great guns but they're not the same gun. In my area Belgian A5's from the mid 70s in a condition worth buying tend to bring $600-$1000(sweet 16 a bit more, maybe $1200 for a nice example)-well within what you want to spend.

Beretta makes beautiful guns in that price range too, but I'm like you=a big (original)Auto-5 fan.