Feeding my Corn Snake?

Hey guys I just got a Corn snake it went into my backyard the other day, I bought a heating pad for it and a light for the top, I'm trying to take good care of her. The temp says its always between 75F to 86F so it seems okay, but I'm not sure how she's doing.I got some mice and today I thawed it out and I put the mouse infront of her but she won't eat it. Can I leave the mouse in the tank? If so for how long, how should I get her to eat, thanks!