Am I feeding my corn snake enough?

I have a corn snake who is approx. one year old. She is a little more than a foot long. I have had her since November and she has always been a good and willing eater for me. She usually sheds every five to six weeks, but she has missed her most recent shedding. Her last shedding was April 13th, 2011. It has been fairly humid lately, so I don't think it is due to humidity. I feed her one pinkie every two days (for example, if I feed her Monday, her next feeding would be on Thursday), but if she is offered two, she will eat both without hesitation and she hasn't regurgitated. She has only been fed two mice at once only two times. Does her willingness to eat both pinkies mean that she is ready for more food? And could that have to do with her missed shed?