You be a furry if you want to be a furry. If you feel like you don't want to be one, then you're not. If you like Anthropomorphic animals for whatever reason, it doesn't make you a furry. You have to just kind of choose to be a furry. It's kind of like other fandoms. You can enjoy the game/TV series and like looking at fanart, but joining the fandom is a different story.
What does being a furry entail? Welp. That's really up to you. There's a lot of different things that can come with it. If you enjoy roleplaying with other people in like dungeons and dragons type scenarios you can do that. If you like drawing Anthropomorphic animals, and like sharing/selling/ buying/trading art, you can do that. If you want to even go to conventions and dance in or outside of a fursuit. You can make and sell fursuits. IF you really like military stuff, there's a whole niche of military furs. And I'm sure there's a lot more furry niches and all kinds of other stuff you can do in the fandom. If you want none of that, you can avoid all of that, and just still be a furry. It's really up to you.
(Though I think every furry should have at least one fursona. A fursona could be a version of yourself that's an anthropomorphic animal. Or it doesn't even have to be you as the anthropomorphic animal, just kind of a for fun OC {Own Character}. To get one, just think up one. You can draw it to represent it, or ask an artist like myself to draw it for you. )