For a first time mother the thought of pain in labour is a scary thought. Because you are small it shouldn't matter, your body will accommodate if you get what i mean.
My first birth i was in pain and then had the epidural and felt nothing, yeah it was great when the pain went but i ddnt feel the birth which i regret now.
My son was born at home by accident which meant i didnt have anything and the pain that i thought was the worst was the burning sensation but i guess everyone is different. Try not to think of that now, you still have ages to go and enjoy the pregnancy