Its normal, some hamsters get out after midnight, or wait till all lights are out... they dont care we have to get up!
If she is already tame, try ruffling the bedding a little and talking, making some gentle noise in the cage - and when she shows her face outside her house, stick a sunflower seed or some small treat in her mouth
Then try to lure her out with a promise of a next one. Do this till every night she will go out to your hand just to get some food! It works with my hamster usually