OK yur 15 years old so belive it or not people don't like to let yung folks on their property alone. So you are going to have to be creative. Sit down and write down a what your going to say to the land owner. In it put down that you have been well trained in Hunters Safety and you have been hunting for so many years. That you are a good student in school.
Belive me I am a land owner in my 50's and I think a well dressed well prepaired young man would impress me. Other suggestions if your dad or mom would go with you showing support that would be good too. If you have any face jewlery get rid of it (ear,nose,eye rings) nothing would make me shut the door faster then a blue haired holly faced kid. Just my suggestion.