Your mobility will be considerably changed. You'll still be able to carefully twist at the thoracic levels, so driving shouldn't be too much of an adjustment once you're recovered enough. You will most likely have pain with sitting, since you need to have some movement in the lurabar area, especially L5-S1, to sit, even if you've got really good posture.
I have 14 levels fused, T4-S1. I am quite limited. I have a swivel disk to sit on to drive so I can turn enough to change lanes safely in traffic. I can sit for 20 minutes to an hour before it hurts too much and I need to get up. I lay down during the day at least once to get the stress off my back.
You'll have a harder time than those with 1 or 2 levels fused, but you'll probably be a lot better off than me. You'll be somewhere in between.
You'll have to decide whether the trade off is worth it. For me, it absolutely was. I have a lot less pain than I had before. Keep reading and asking questions. That's the best thing you can do for yourself as you try to make a wise decision.
I wish you the best,
Emily