Longboard Size for 120 lb woman

Hey Everyone, just been lurking for a bit on this forum but this is my first post...
Anyways, I got my girlfriend into surfing and right now she rides a crappy 9 foot surftech soft top which she can now pop-up easily on white water.
She's a little freaked out to go out into the actual waves right now (we surf in La Jolla Shores, San Diego) since the last time she did, she ended up pearling and the board smacked her in the face.
So the 9 foot surftech soft top is a bit heavy (I ride a 8'4 Ben Aipa Epoxy and it is probably 3 times lighter) and it's kind of hard for her to carry that through the surf.
I was wondering how short of a longboard she can go while still riding it like a longboard (trimming, gaining speed by walking up and down the board instead of rail to rail).
Any tips from a female longboarders would be great.
Thanks!
Tony -
Anyways, I got my girlfriend into surfing and right now she rides a crappy 9 foot surftech soft top which she can now pop-up easily on white water.
She's a little freaked out to go out into the actual waves right now (we surf in La Jolla Shores, San Diego) since the last time she did, she ended up pearling and the board smacked her in the face.
So the 9 foot surftech soft top is a bit heavy (I ride a 8'4 Ben Aipa Epoxy and it is probably 3 times lighter) and it's kind of hard for her to carry that through the surf.
I was wondering how short of a longboard she can go while still riding it like a longboard (trimming, gaining speed by walking up and down the board instead of rail to rail).
Any tips from a female longboarders would be great.
Thanks!
Tony -