Hi Anonymous,
you can definitely ask and usually there are no issues in postponing. I would recommend creating a calendar with a specific action plan in order to estimate when you could be ready, you can find some suggestions on how to proceed on that at the following link:
Best,
Francesco
Yes of course you can! Just give them a realistic time when you would be abe to do the interview, so you don't need to pospone again. Your interviewers will not even know you postponed, since they have nothing to do with the management of the process.
Cheers, Sidi
There's never a downside to asking if this is something that would help you. Consultancies want you to be at your best, and no-one wants to waste their time with a candidate that just hasn't had time to prepare properly for one reason or another.
March is still far enough that BCG may be able to accomodate. Worst case, they tell you they can't and you come as initially scheduled. The people making the hiring decision are different from the ones doing the scheduling, so no harm done.