So sleepy.....

How is it possible for a little baby to fight falling asleep? We've been working the last couple nights at getting Ella to sleep in her crib and both nights have ended up with her sleeping with us in bed. Tuesday night we were up until 2 and last night until 11:30. I think Ella could stay awake all night fighting against being put down in her crib.... I know she's tired, but man she fights it! Is this a sign of her personality we'll see as she gets older? Should we be afraid? We could have our hands full!