my girl is 5'4" and around 125lbs(asians are petite!) and im in the same quandry dude.
I was gonna go something like a 145cm or 143cm, but IMO its definately better to go with something a little small and lighter for chicks.
If its a bit too big/unwieldy for them then chances are they will just pack it in right away.
Ima pick up a smaller, second hand board for her initially and then if she still likes it after a big season we can look at trying a bigger, new board!
The only thing better than a healthy addiction is a healthy addiction you share with your significant other!