Being you doesn't usually help. But being 18 also doesn't mean you're a "young punk".

If you're done asking for permission and they still think you're a "young punk", then you probably are. From your posts, I don't think your a "young punk" so niether should a landowner. The purpose of all of these tips people are providing is to help the landowner form an opinion of you. It's your job to make sure that opinion is a good one.

I think your best bet is to build a network, ask old high school classmates, co-workers, friends of your parents, friends of yours, neighbors, anybody, if they no somebody that owns the piece of land you want to hunt. Don't ever be afraid to name drop, just make sure the landowner knows and likes the name you use. A good approach might be:

"Hi my name is __________ I'm a friend of _________ and he/she suggested I come introduce myself to you".

Don't get too discouraged with the rejections, all you really need is one farm for now anyway.