IIT Roorkee metalurgy or IIT Guwahti Engg phy or IIT Ropar CS.?

friends m in lil confusion...i got AIR 3446 in JEE this year...according to last year cutoff i will easily get Metalurgy in IIT roorkee and Engineering physics in IIT Guwahti...and i am also hoping to get CS IIT ropar as per previous year data.....so please suggests me what to do now...no doubt i am intrsted in CS but is it right to take risk with new IIT's..??....hoping for quick rply...thnx in advance...:))