Hello,

Admission in VIT in any of its branches is given on the basis of their own entrance test called VITEEE. It is generally held after JEE mains in the same month and is an online Computer Based Test. Based on your rank in VITEEE, you are called for the counselling being held by the college. Computer Science Engineering with specialization in AI has been introduced as a course in 2018 only and took admission through the VIT counselling. You can take admission in your desired course but as your rank gets lower in the entrance exam the fees you have to pay for the same course drastically varies. For example, if you take BTech CSE in category 1 (generally below 1000 rank) you have to pay lesser fees than one taking Btech with 15000 rank and taking admission in Category 5. 

My suggestion would be that you study well enough to secure a decent rank in VITEEE and then try via the counselling. Here is the link for the exam to keep you updated https://engineering.careers360.com/exams/viteee.

Thank You