DS was breech from at least 28 weeks down and he never turned. my water broke at 37 1/2 weeks and I had my C/S then. I wasn't interested in turning him though - I was quite happy to get a c/s.
There's still plenty of time at 30 weeks. There are things you can do to help him turn/stay head down. check out http://www.spinningbabies.com/
If you want to, you can ask for an "external version" where they try to turn the baby manually at term. I believe they do this around 37 or 38 weeks, though, because there's a chance you could go into labor because of the procedure (or the baby can have distress, and they need to induce). I have heard the ECV is quite painful though.
For breech, they don't rush the c/s - I'm sure it's doctor-dependent, but there is no urgency, so if they book it, they can book in the 39th week (when it's safest for baby) and if you happen to go into labor sooner, they just do it at that time.