I previously held an f1 from 2004-2008 for undergrad. Returned to my country (india) in 2008. Decided to come back for grad school so applied for a 'prospective student b2' in jan 09. Came to the US on the b2 and received acceptance from grad school... so now I want to change my b2 to an f1.

The thing is that my classes start aug 24th and I just have a bit over a month before then... do you think I stand a chance by doing a COS and getting it approved in time? Or is it too risky and I should return to my country to get the F1 stamp? Shouldn't it be faster for me as I clearly stated in my b2 visa app that I was a prospective student and I would do a COS? [currently USCIS states that the wait time for COS is 2.5 months avg]

Please advise ASAP!!
Thank you!

It won't be any faster because of your visa classification. The USCIS doesn't operate that way. Timing is difficult with F-1 COS cases as the I-20 and start of class must be within 30 days of your B-2 I-94 expiration.