Yoga practice seems to be used to access some deeper dimension or some enlightened state. Understand right now there is no connection between flexibility and enlightenment.
Your physical capabilities have nothing to do with higher consciousness. The depth achieved in any posture only has the ability to hurt or help your body.
Please stop worrying about how much you can do! STOP judging yourself and others on physical abilities and prowess, stop believing MORE is better, stop the madness!
There is no reason to not trust your process, no reason to get frustrated, no reason to criticize, or judge others, nothing wrong with getting old, or not being able to get pregnant, or being handicapped, or being short or tall or gay, or injured, or divorced or married to an idiot, or with Christianity or Judaism or Islam, or indigenous beliefs, or pollution, crime, war, Bush, etc. When this understanding grows, we realize where we're at now is just as perfect as wherever we could possibly get to.