i know that shortboards arent good begginer boards
This is quite a sweeping generalisation, but true in many respects. The length/ style of a board is not the only consideration. You have to consider; your height, your weight, board thickness and width, power of waves you are likely to ride and (as you have rightly guessed) how often you will go and therefore how quickly you will progress.
If as I imagine the FL in flsurfer stands for Florida, USA then the chances are you will progress pretty quickly, because you will get good conditions more often.
There is one other key issue you want to consider. What kind of surfing do you want to do? If you are going to want to charge with radical new generation tail slides and aerials, you will need to have a shortboard. If you are after mellow carving, sweeping turns etc then a longboard is for you. If, like me, you are after a combination of the 2, then a mini-mal is a good option.
If you choose a shortboard, you need to think about buoyancy. If the board is like my old one - 6'6 X 18" X 2 1/4" then you will struggle to catch waves and when you do your rides will be shorter and the board more difficult to stand on and control (especially when you are still catching whitewater). Look for a board that is fairly wide and fairly thick. This will mean it will last you longer. You may find it a little harder to get the basics down but at least once you get up and riding, you will be able to do more on it. If you buy a true beginner board, you will out grow it very quickly.
I'll post some more tips on how to get to grips with the basics if you like.
Actually if you look at the thread called 'Now that I've caught the wave, what do I do?' I posted some details of how boards work and how you control them, this might help you choose what's right for you and give you some pointers about how to progress.
An option may be for you to rent a beginners board until you get used to catching waves and getting to your feet and then buy a shortboard once you have got to grips with the basics.