So is NOT the way to start every sentence!
So!
If you listen carefully, you will find that many people start every sentence with the word so because they like it so much . . . but, actually, that’s not the best use for the word so! Here we will look at how to use it properly.
1.) Use “so” to express a lot of something. Used this way, it is a little like the word “very”.
She was so happy she cried.
Everyone loves him because he is so kind.
2.) “So” also means “to a large degree”.
She talked so fast I could not understand her.
Don’t look so worried.
3.) You can use “so” to say “yes”.
Is it going to rain today? I think so.
Did she pass her test? I think so.
4.) You can use “so” to mean “true”.
I heard that you are a writer. Is that so?
So is also used to join parts of a sentence.
5.) So: “in order that”.
Will you hold my books so I can put on my coat?
They whisper to each other so no one else can hear.
6.) So: “for this reason,” or “therefore”.
I need to learn English and so I started taking lessons.
I was tired and so I didn’t go out with my friends.
7.) “So” can be used to begin a sentence if you want to know the answer to something. 
My brother failed his math exam! ….……………………………………………………………………….. …….So does that mean he won’t get into college?