Car ignition problem

So, I have a 2003 Honda Element.  

In the last couple of weeks, I've had something weird happening when I turn the car on.  It only happens occasionally--first it was once or twice a week.  Lately, it's been every few days.  

Sometimes, when I turn the key to turn on the car, the engine turns as usual.  But then it makes a cranking sound--the same sound it would make if the car were already on and I tried to turn the key again.  I'm not turning the key any longer than usual. However, I usually get spooked when that noise happens and turn the key back to the off position.  When I try to turn the car on again, immediately after, it turns on just fine.  

Again, most of the times I turn on the car, it works just like normal.  
But, this oddity is happening more frequently and I'm worried it's going to be a significant problem soon.  

Starter?  Battery? Fuel pump?  Help a girl out.  

Thanks!