Do I have Social Anxiety Disorder?

Alright so I think I have Social Anxiety Disorder. This is because I never want to go anywhere like Christmas parties or baby showers because I'm scared to see anyone in my family. Especially my cousins. I get nervous when anyone I don't know very well either comes to my house or someone's house I'm at. I ALWAYS ask who's going to be at certain places that I'm going too. Also, the first few weeks of every school year, I always get queasy and self concious. There's also a lot more too. I'm 12 years old. Do I have Social Anxiety Disorder or am I just shy? FYI, I've been like this since I was little. I also wanna know if there's a certain way I should address my parents about this and if any of you have SAD, what are some exercises you do to calm yourself in these situations or to temporarily dismiss the feelings of anxiety. Maybe some tips? I JUST NEED HELP