Visitor Visa - B2

 I'm 2nd year bachelor student living in Sweden with a permanent residence permit. My family also lives here, my mother, step father and sister. I want to take a trip to the us during the school break, for sightseeing and vacation. Some information about me and my application:
-I want to go for 3 weeks bc i need to get back for school
-All the ties i have is in Sweden, bank accounts, family, school, student help...
-My mother owns an apartment here in sweden and she's also the one paying for my trip, as i stated in the application
-I'm a second year student with with student help as income
-I have a friend in the east coast and she said it would help if she writes me an invitation and send me proof that she goes to college in the states.

Would the invitation work against me or should I not mention my friend at all?
What are the chances of me getting a visa in sweden?
Also, i'm worried that my documents won't even get looked at.

I'd love to hear your opinion and advice if you ever been in the same situation or has ever apply for a visa in sweden or the nordic countries. Thank you very much!