Guys, im gonna use a new Maxis number for my Iphone 3gs..currently using Celcom. Do I need to create a new number/account before I get my Iphone on the 31st or can I do it on that day (im getting mine at Machines btw).

Machines guy said better I get new number 1st and then they will change the plan for me coz activating line could take 2-3 days

Im afraid if I get new number now later cannot change plan or something. What do u guys think