It took me 5 days. to get all the way to superior.
I decided 5 days ago I wanted to do alchemy. I got junior alchemy the day after. I trained it for 2 days while getting stuff for superior. I got superior yesterday. I bought the devil's star piece. and the stars took literally 2 hours. There are a lot more star quests than you think. Death quests help a lot. I killed Maggie. And it was relatively easy. i did the quest with just 2 of my rb's.