I am at level 56 and erased all my previous saves, so going back is not an option. At the College of Winterhold I started the main quest line early on, at level 12.
I went up to 'Hitting the Books' and stopped for a while, then went back at level 40ish and did 'Good Intentions'. But after the Archmage died in 'Containment', Mirabelle won't give me the rest of the quest. She was outside instead of inside when she told me to look for him and I can't do the rest of the main quest chain for it. I have done every other guild but the college and refuse to start over.
I am playing on the Xbox 360.