hey nino. i went on vacation the summer before i went to mac.
yay vacation! i didn't review at all and it was really bad cause i took calc in gr. 11 so it was a long time since i've done math. i had my biology and chem during the first term of gr. 12. so if you think about it... i didn't do any calc, bio or chem for 7 months! i never reviewed a thing before i went to uni either.. maybe i should have.. lol.. anyways.....back to the point
I think it was fine actually if you don' thave the time to review. During the first week, all your classes will just be basic review. so for your first 2-3 classes its review. Then they start building on a bit. but really, some of the stuff i leanred throughout the year, i felt like i have already learned in highschool (but keep in mind, my highschool is different from yours). If you do have the time, i woudl suggest just skimming through your highschool notes. GEnerally, i wouldn't worry about it as much cause they will review and make sure everyone will be on a similar pace during hte first week.
if you realise you dont' rmb anything during the first week, then start reviewing more!!! that's what i think.. enjoy your summer!