Ask your parents and see if they can give you an addon card. Most addon cards will report to CIBIL and get your credit history started.
Otherwise, for most unsecured credit cards, you need to be 21 years old (3rd year) AND you need a very good CIBIL history OR income docs.
So, the best you can do is to get yourself eligible for good cards and higher credit limit by building credit history before you get your first income.
For building that history, I will suggest BNPL - LazyPay, Amazon Pay Later, Uni, etc. They are OK when you don't have credit cards. Just for getting the credit history started at least.
After that you can keep 10-20k in savings accounts like Kotak 811, HDFC DigiYouth Save, and other low MAB accounts to get pre approved cards from those banks. Some PSU banks will not have pre approved offers but they will allow students credit cards, e.g., SBI agent called me up for CC without income docs based on my savings account (not pre approved though), using something called Project Shikhar.
The agent ticked student as profession for me and I got a 10k limit card, I only have 5yr old savings account (with 500rs or so balance when he called me). So that's one way. But they have a list and you need to be on that list, I guess I turned 21 recently so they got my name there.
The main reason why I applied as student was because SBI requires 25 years old for self employed like me so it was the only option. But all banks don't have the student option. Planning to wait for credit limit increase and upgrade to a better card.
Once you get a credit card with 50k-1L+ limit, you can apply for other cards using card to card only. All 4 of my cards are without income proof (although I am a student and self employed professional, both).