Hey, I'm in grade 12 and I was thinking of applying for medicine before.
Some of my friends have applied for medicine so I can help, to apply for medicine you need to give the UCAT, you would need a score of 2800+ for a good chance to enter a uni.
Also, medicine is really hard for international students as universities typically reserve a few seats for internationals, could be 3,5,10,20,etc but they are usually pretty less. So, you can't aim for 'higher-ranked' unis, both of my friends who applied for medicines get 95%+ overall and their top choice is Birmingham I believe, you usually have to give BMAT for higher ranked universities like Oxbrige,UCL,etc.
You need to get some work experience and good scores, your predicted depends on your teachers, they could calculate it from your 10th,11th and 12th mid terms, your improvement over the years, etc.
typically AAA=90%(CBSE) for higher ranked universities and 85% for the others, but you'll have to score a lot higher than this as most of the applicants will be high-scorers.Moreover, you have to apply to 5 universities, 4 will be for medicine while the 5th one will be your backup(for which you'll choose a BSc programme)
You're gonna have to send your application by 15th October, so make sure you SOP is perfect and is ready before your mid term exams(ideally) after that you're gonna have to give interviews, make sure to read up on FAQs and try to find some former applicants in TSR for help.
Hope this helps!
feel free to pm me