Just that really!
Can't decide!
And also how would they all be pronounced??
I'd say:
Carys - Ca-riss
Cerys - Ke-riss
Kirsten - Ker-stun
Kirstin - Ker-stin
And could /would they get shortened? Carrie / Kerry / Kirstie / Kirsty / Kirst / Caz... ??
We're in England if that makes a difference.
Thank you!