Whilst not five pointed, there's a prominent star on Diana's inherited head piece.
In Babylonian symbolism, the goddess Ishtar is represented by an eight-pointed starburst and she is associated with the planet of Venus.
The Romans equated Aphrodite with Venus and, today, some people equate the Greek Goddess Aphrodite with Ishtar. Both goddesses represent lust and sexuality, although Ishtar also represents fertility and war.
In an interview with the Hollywood Reporter, costume designer Michael Wilkinson expands on his choice regarding the star:
The tiara was an interesting challenge. We thought, there’s something
sort of girly and princess-y about the word "tiara," so we thought we
should use the word "headdress," which sounds much more tough and
warrior-like. So, for the headdress, traditionally it’s been a classic
five-pointed red star. I looked more into her legacy and I chose a
gold pointed star, based on an iconic Greek star. I thought that would
be appropriate knowing her background, and so I created a different
shape for the star. Of course there’s all sorts of things she has such
as the eagle and WW motif throughout the costume, so I tried to use
that WW motif through the belt and the gauntlets and across the
breastplate. There’s WW throughout the costume. I think someone tried
to count them and they got to 40.
The pentagram itself is not uniquely American and is a common ideogram used throughout the world. The use of a five pointed star originates from European or Western heraldry, and the golden five-pointed star has associations with military power and war.