Hi Rawr, I would strongly suggest to hire an 8ft standard board for a couple of times before you commit to going short on a hard board!
Why , soft foam boards are made to be wave catching easy paddling catchers, fiberglass not so much 8ft might give you lee way but going shorter early will be much harder.
At what level are your skills , can you turn the board and go across the face? can you turn the board in functional turns.
Are you out of the white water surfing yet?
Rough questions, true but unless you have some basics on the foamy you could be jumping too far at this stage.
If you can hire then try an 8ft board and a shorter one, you will then be able to really evaluate the differences.
Roughly where are you surfing that too can make a big difference to your experiences but don’t worry short boarding will be achievable.
A tip……. if you are thinking of any board as a purchase, post a picture we can advise whether it could be suitable

I've taken up troll hunting just for fun, instead of a rifle I'll just use a pun! 冲浪爷爷