Looks like you are getting a lot of good advice, most of it I agree with.
As for the shot gun you use, use a 12 ga if you can handle it. That is the key question, what can you handle? Only you can answer that question, by practicing at the range. If you can get good groups at the range with a 12 ga use it. If not go to the 20 ga, the 20 ga will easily kill a deer. I would not go smaller than a 20ga.
Since this is your property, the best thing you can do is scouting. Like other members have said, check out the deer patterns. What time of the day you see them etc. I do not put too much faith in scrapes and buck rubs. I know the bow hunters would disagree with me. Rubs and scrapes are good, they are the most visible sign that deer are in the area, but they do not necessarily tell you how they are moving. Scrapes and rubs are made only when the deer are in the rut and can be abandoned or change quickly.
I think the key is funnels. A funnel being a narrow stretch of woods, a valley, a field edge, a creek etc where the deer are consistently moving from the bedding area to where they feed. Look for heavily worn trails within or near these funnels. If you find good scrapes and rubs within these funnels even better.
You may want to go on-line with your computer and get a topographical map of your property and near by properties. This may help you identify certain funnels.
It is good to see a young person getting into hunting.
Good luck and tell us how you do.