Im i shy or autistic?

I'm actually exactly like this except the speech impediment although I do stutter when I'm nervous. I can't go out for more than a few hours or I get very high anxiety. I can't concentrate when I'm talking to new people becauseI'm so nervous as to what they think of how I'm acting (if I'm acting normal standing normal saying normal things?) I always just labeled myself as being socially retarded. I mean in school I was semi popular but I was a nervous wreck on the inside. I only talk to people if I have to. Even with my bf's parents (we've been dating a year) who I know pretty well it's very very hard for me to talk with them. I just like to be alone with my animals in my room or outside riding my horse and I've accepted myself. I mean to get over it I guess I could force myself to talk to new people and go out more and more over time but I don't mind being the way I am. I'm 18 btw