help me find this manga!

Hello, I'm looking for a manga of the reincarnation genre, the girl reincarnates as the daughter of a noble owner of a territory far from capital (the story begins she's already adult) and I believe that in history the prince or someone 'one of the high nobility is going to see her for a reason that I have forgotten she takes her around the territory and she ends up showing him the invention that she has recreated (like the train of which she saw a model and that she remembers it) at one point she ends up showing him something else by making him promise to keep it secret, the object in question is a cannon and he realizes that if ever this invention comes out to the outside world the war will be changed .... I stopped there someone has an idea of the manga?
Thank you for your help ! Sorry if it is not too understanding it is not my native language!