Mini Mal?? Longboard??

Hi,
I'm new to surfing and i have taken a surfing lesson and i stood up after a couple of minutes and then caught waves pretty often. Now, i am keen to continue, by buying my own board. I have done quite a bit of research about surfboards and i still am not sure whether to purchase a longboard or mini mal. I like the longboard because of its buoyancy and being easy to learn on but i'm also interested in the mini mal because it can be used as a longboard aswell as a shortboard - for after i have mastered longboarding. I am 14yrs and 5'6. Advice would be greatly appreciated.
I'm new to surfing and i have taken a surfing lesson and i stood up after a couple of minutes and then caught waves pretty often. Now, i am keen to continue, by buying my own board. I have done quite a bit of research about surfboards and i still am not sure whether to purchase a longboard or mini mal. I like the longboard because of its buoyancy and being easy to learn on but i'm also interested in the mini mal because it can be used as a longboard aswell as a shortboard - for after i have mastered longboarding. I am 14yrs and 5'6. Advice would be greatly appreciated.