Corrected quest reqs.
I'm pretty sure this quest needs 100 Destruction, NOT 90. Some other Ritual quests need 90 in their respective skill (I think the Conjuration one only needs 90) but this one needs 100. Someone prove me wrong?
I changed it to 100 as i am 100 destruction and i could start it not sure how to change the words under her picture, but done my best :)
Updated with new information Edit
as about please read http://www.uesp.net/wiki/Skyrim:Destruction_Ritual_Spell about having 100 destruction