Do not adjust the body by moving your head, back and limbs to get comfortable. Whilst your body may feel different or even uncomfortable after a posture it is important to let it lie and just settle into a new way of being. Take yourself a little further each time . Don't physically push yourself but rather bring your attention to the part of the body which resists the movement and consciously try to relax that part. Use your mind, rather than brute strength.
Yoga is an entirely personal experience.
There are no goals which pertain to the whole class. Given any one posture, someone in the class will feel it in the knees, the next person in the back. Another will complete the pose as if born for it, yet find the next pose arduous. No matter how the pose looks on completion, if your focus is strong and connected to the body the yoga will be having a positive healing effect appropriate to your body and mind. That is, comparing your posture to the next person is meaningless.