I'm really sorry if I am making assumptions, or of this isn't what you want to hear.
But it sounds from what you're saying, like you dn't want to go.
I can see that you see all the positives etc. but if in your heart of hearts, you don't want to go and are scared of leaving behind your support networks, I would advise you to speak to your parents, because at the moment it seems like you would be really unhappy there. And if you think you will be unhappy, it will become a self-fulfilling prophecy as you will be less inclined to go out and make friends and enjoy yourself.
Again, I am sorry if I am wrong! But I think it will be best for you to speak to your parents about staying. Either just you, to finish your studies opened go out later, or all of you.
It sounds awful, but you need to be selfish hun!
Hope it goes ok!