No matter what breed of animal, you have to understand a little of the physiology of cattle, and growth. A beef breed, such as angus, will usually come off it's dam at the 4-600 lb size at about 5-7 months. You will need to keep it for at least another 6-8 months in order for it to grow its' body, bone etc, and for it to put on a respectable amount of beef. Also understand that an animal will not start to marble --- which is what gives the meat some flavor and makes it a more enjoyable eating experience by actually providing "grease" in the beef --- until it reaches a certain stage of maturity. I am not saying to eat half fat, but the marbling makes the meat more tender as it cooks and makes it more juicy to eat. If you "pour the feed" to them, they will gain quicker, but will put on some more "outside fat" than actually marbling.
As Kenny said, a jersey will make very good beef. Jerseys are the 2nd best marbling beef, behind Wagyu, but understand the fat is yellow. It makes the meat a little more "sweet" tasting but I have been eating jersey beef for over 30 years. They will be about 2 when they are ready to kill. Dairy breeds will grow more bone, size, at first rather than put on as much muscle/meat. But they will be ALOT cheaper for you to buy and will make very good beef.
I definitely would get 2 to raise as they are herd animals. One will be more likely to want to go looking for company. You can raise 2, then sell one to help cover the costs of raising them. Or give beef to family members for Christmas presents. Get steers as you will not want to deal with heifers coming in heat and a bull is just not for a beginner.
Most beef animals are in the 15-20 month age when they come off a feedlot. And it is very true that the feed lots do not use any more antibiotics than are absolutely necessary as they are very expensive and the laws for drug residues are very strict. The hormone implants are another thing and I get the feeling that is what you really are wanting to avoid. I am with you on that.
There are books that you can read, try some of the "Storey Publications" that are available from some TSC, or find on line. They are great for beginners to at least get some basic knowledge from. Try some of the homesteading type publications, lots of the magazines again at TSC. Countryside, Acres USA, Stockman Grass Farmer, many others. You won't learn everything from a book, but it will give you some very good basics to draw from.