Yoga is about gentle balance. A yoga pose is about using body weight and strength to oxygenate. The only way to improve is to gently push the body beyond its comfort level as technique improves. Going beyond the limits means losing balance and sometimes falling out of a pose. Don’t get frustrated when a pose ‘breaks’ and you find yourself flat on the mat. Falling out and learning how not to is the way to improve.
Gently push yourself everyday, and remember if you are forcing it then it isn’t yoga.