Hi Evelyn, welcome to the world of Chanel
Is there a boutique near where you live? Then I would suggest that you try out the Medallion and the classic flap first and see what suits you the most.
If you always have your hands full, then the Medallion and the classic flap maybe won't suit you, since they are a bit more difficult to get in and out of, like Swanky said. You should certainly try out the PST and GST. But there are so many wonderful bags out there, one of them will be the perfect Chanel bag for you, I'm sure
Good luck with your decision!