Hi there,
Hope you are doing well.
With 15718 rank in VITEEE, there is no probability of you getting CSE at the VIT Vellore campus, since in the previous years, the closing rank was around 7k-8k.
Also, IT in VIT Vellore is a little probable as for previous years it closed for 17k in 2017 and 12k in 2016.
But, you have complete chances for CSE at VIT Chennai campus( closed at 33k) if you like to give it a shot.
Hope it would help.
Thank You.