Thanks so much ladies for your supportive words. It really means a lot to me to know that others think I am doing a good job don't we owe it to our babies to give it a really good go! I added up what I have expressed over the last few days vs what she is actually drinking and this is what I got:

Sunday
Expressed 640
She drank 520

Monday
Expressed 770
She drank 545

Tuesday
Expressed 725
She drank 545

So it looks like I am pumping more than she needs already. I know that I could pump more out of my breasts but I am worried I will go into overdrive so I might just keep expressing slightly more than she needs that way I am staying ahead without creating too much of a problem.She is only 13 days old but as you have all said, she will start wanting more shortly and I want to be prepared