I recommend postponing the SSD BIOS update until you back up your data. You will need a drive with enough free space to accommodate the backup. I installed the BIOS update on my Samsung 840 500GB (non pro) with no data loss. I did a backup first, though. It may be a good time for you to consider a regular backup strategy.
Yes, that's exactly what that means. In my opinion you should be backing up our computer anyway. All harddrives fail eventually. The hope is that they last the life-span of the computer, but there again everything can and will fail eventually. That is a universal truth :-)
You can get an external hard drive for very little money. I personally like the WD My Passport drives. at $60/terabyte you would be wise to buy one of those and backup your data regardless.
Iam on a Macbook running time machine backups every hour to my external WD drive. There are similar applications for Windows or you can backup manually if you wish, but whatever you do I would definitely be backing up my data one way or another.