Which size board would you recommend??

Hi, I know this question gets boring, but buying the first board is an important step and I need all the advice I can get so I can make the best choice possible!
Firstly my stats, I'm mid twenties, female, 5'4" tall and weigh around 125 lbs.
I have been surfing for 2 months now (about twice a week on average) taking classes. In the class I use a 7'2" softboard and can stand up well on broken waves. I have also tried my friend's 7' fibreglass funboard and was able to stand up on that too.
I will probably get at least another month's surfing under my belt before I actually buy my first board too, and am definitley looking for a second hand fibreglass, I'm just not sure on the best size.
When I buy the board I hope to increase my water time to three or four times a week, and I will still take classes every so often as I am keen to improve and progress. So am looking for something that will suit me now but will enable me to progress nicely too withouth the need to upgrade and resell too soon.
(And before anyone points it out - I have already asked at the school, and the answers have been slightly varied, so I figured I will get as much advice and tips as possible and then make an informed decision!)
So shoot away, tell me what you think . . . .
All suggestions greatly appreciated!

Firstly my stats, I'm mid twenties, female, 5'4" tall and weigh around 125 lbs.
I have been surfing for 2 months now (about twice a week on average) taking classes. In the class I use a 7'2" softboard and can stand up well on broken waves. I have also tried my friend's 7' fibreglass funboard and was able to stand up on that too.
I will probably get at least another month's surfing under my belt before I actually buy my first board too, and am definitley looking for a second hand fibreglass, I'm just not sure on the best size.
When I buy the board I hope to increase my water time to three or four times a week, and I will still take classes every so often as I am keen to improve and progress. So am looking for something that will suit me now but will enable me to progress nicely too withouth the need to upgrade and resell too soon.
(And before anyone points it out - I have already asked at the school, and the answers have been slightly varied, so I figured I will get as much advice and tips as possible and then make an informed decision!)
So shoot away, tell me what you think . . . .
All suggestions greatly appreciated!
