I am starting my leave in a couple of weeks when I'll be 30 weeks. People told me that this was too early, they managed to work longer etc, but it's a personal choice.
I actually wish I'd started leave earlier than 30 weeks as my job is very physical & I underestimated how tired & uncomfortable I would be at this stage. But I only have 7 more shifts so there is light at the end of the tunnel!!
Do what you are comfortable with. If you're not willing to drive 2 hours from your hospital then don't - yours & bub's health is more important.