I fought Diablos as soon as I got him too. I went back to Balamb Garden and saved by the directory and beat him. He was pathetically easy once Selphie blinded him. The whole battle I was sitting there testing magic Selphie got on her Slots while all of my characters had 1 HP.

After I had Diablos beat I went up and won Seifer's card from Cid.
yup...me too...i had quistises card aswel and lots of other pretty good cards...

i didnt go to the trainin center until after the seed ball with quistis....i am doin a fairly low level gam eand then levelin up with bonuses at the moment....but it was easy...all you have to do is cast blind or junction it to status attack...easy peesy......and blind doesnt wear off like sleep....