Help fight trespassing ticket

While my daughter and I were on a buck hunt for her we crossed private ground that wasn't posted. Myself and close friends and family have hunted this area for years .Never had a problem until this year . while trying to retrieve my daughter's deer we had crossed private ground that wasn't posted .had we known the land was private we wouldn't have been there .we are asking for help to fight the trespassing charge that I received for trying to retrieve an animal that wasn't harvested on posted or cultivated ground . We had no sign of being on private ground .we try to respect the land, animals and the landowners .  We appreciate any help we can get