really low mmr

So i just calculated my mmr on and it says i have 935 mmr. Thats really freaking low. So im kinda scared to do my placement right now. Can i raise my mmr with normals? or is it only in ranked? And why does my friend who has a 40% winrate have 1300 mmr while my winrate is 70%?
Report as:
Offensive Spam Harassment Incorrect Board