Most couples will be pregnant within 12 months so I think you'll find at your age your doctor will not interfere anyway. My GP was reluctant to start investigations after 9 months of trying and 1 early m/c and I was 40 at the time. I switched GP's and she started the ball rolling.

I would not recommend getting testing yet. If you think it's stressful ttcing now, it's far worse once you start the whole investigation process, so leave that until you need it after 12 months. Hopefully you won't need it though.