Welcome to BYC. Glad you decided to join our flock. Your hen is very well insulated with feathers and should be able to keep the eggs adequately warm even if the temperatures cool down (as long as it doesn't drop below freezing), but my biggest concern is the number of eggs under her. She has to be able to cover all of them with her body. I always limited the number of eggs that I allowed my hens to sit on to a dozen, so I would take about 8 of those eggs (the ones on the outer perimeter) out from under her. Also make sure that she has food and water very near the nest box. Please feel free to ask any other questions you may have. We are here to help in any way we can. Good luck with your hatch.