I completely understand your scared-ness. I was terrified to go into the place. Something that eased my anxiety was marching band. I understand you can't just jump into something like that, but try to find some organization or school activity that you like, you'll meet people that relate to you and are nice to you.
Now I understand we are very different in real life, you coming from being home-schooled and being slightly shy, and I am the kind of person that kind of just talks way to much and used to be SUPER DUPER annoying in my earlier years, but I can still relate.
The most important advice I can give you is to
be yourself. Don't get into something you're uncomfortable with and if this means you have to sit very quiet in class for the first month until you can find people you want to get to know, then do it. People are less scary then they appear
Don't over-approach people and don't under-approach them. If you want to make friends/make acquaintances just approach in conversation and find people with similar interests, like I said before.
Be confident. People aren't out to get you and if you don't give them a reason to dislike you, you'll be fine.
Trust me, you will find friends
