Hello Joey
Not sure why you mentioned you're biologically a male x3 You don't have to be a male or female to be in the fandom. Everyone is allowed to be a furry.
As for your friends saying that furries are cancerous and autistic, I would say from a personal standpoint they have had little to no experience with the fandom. Anyone can be a furry and while we have a lot of young members in the fandom, we have quite a large range of people with all kinds of different ages. Different hobbies, ethnic backgrouns, etc.
Generally the thing we have in common is 'furry artwork', as HellEye pointed out. You don't have to like the artwork to be a furry, but generally this would be the best description and is the most common. The fandom revolves a lot (if not mostly) around artwork and creativity in general.
If you think that is weird, think about all the cartoons and movies you used to watch when you were younger (or perhaps still do). Jungle Book, The Lion King. These are just a few examples including humanised, talking animals with personality traits, facial expressions, feelings, etc. These animals have been
anthropomorphised (anthro = man or human, morph = shape or form).
You can like fursuiters (for example), you can dislike fursuiters. Fursuiting or liking fursuits is
not a requirement to be a furry.
Generally there is a huge range in the furry fandom of things you can like and not like. So basically what it comes down to is: You are a furry if you say you are.
Anyways!
Welcome to the forums and the fandom. I do hope you stay, but I hope whatever the decision, we made you feel less weird around furries