1st you are never to old to get into hunting! and you may feel bad about it because you have never done it. A lot of us hunters do not feel bad about it because we do not let the game go to waste. We all respect the animals we harvest.
You could start watching hunting shows but a lot of them are just made for tv. I got a pack of dvds called Drury Outdoors Dream Season 3 and thats some of the more realistic bow/rifle hunting shows i have seen.
Your 19 so if your not gun shy i wouldn't start out on a small caliber unless you want to. Great deer calibers are .270, .30-06, ,308, .30-.30. If you are gun shy and want a gun with knock down power go with a 30-30.
You will learn a lot about hunting if you just start cruisin this forum.