I'm no expert, but not being able to do all the poses is normal; it takes time for some of us! I've never been a particularly flexible person, but regular yoga has helped me change that. I think a better trip would be to a yoga instructor who can correct your form and provide you with modifications that suit your current skill level.
The more you do it, the better you will get.
Focus on your breathing; that IS the key to the relaxation. When a pose is hard, focus on getting deep belly breaths, not on getting deeper into the pose. The better you breathe, the more you will relax, and the deeper you'll be able to stretch.
Writer, mother, wife, and breadwinner. I love to run, but running doesn't love me, so I'm switching to my low-impact bike.
I'm not pregnant, just fat: My blog. fatnotpregnant.blogspot.com/
| current weight: 190.6