Hello Rohita,
I'm so excited to hear that you're first cruise is on the Disney Magic! You and your family are going to absolutely love it!
If you have not already done so, please call Disney Cruise Line and specify your dietary needs to the reservationist. They will make a note of it on your reservation, and you won't have any issues. To be honest, I don't remember there being indian food on the menus, but the chefs onboard may be able to accommodate this request in some way. When you meet your servers for the first time ask them if this is possible. Many times the chef will come and speak with you about your preferences.
As for the bottled water, yes, you can bring it onboard in a bag. If you don't want to carry it with you, you can preorder it through Disney Cruise Line's
Gifts & Amenities and have it delivered to your room before you even get there. Very convenient service:)
I hope this helps Rohita. Thanks for visiting the Moms Panel. Have a magical sailing!!!!