I think the head is proportioned fine. The cat's expression seems more pleased than surprised and is very cartoon like. It would make a great character. The rear quarters appear to be lifted off the ground, like she is not actually resting on her haunches. That may be where the appearance of surprise comes from, she is ready to bolt! Excellent work, I myself have slacked off in my drawing practice and feel like I have slid back on my skills. You inspire me to get back to it. Thank you for sharing your artistic process an progress with us.