Hello Student
Don't get confuse!
After schooling, students go for various courses.
If you want to pursue MBBS or other medical courses, you need to give medical entrance exams. AIPMT is all india test for getting admission to medical colleges all over India. AIIMS is specifically for AIIMS (All India Institute of medical sciences)
Taking Coaching will be fine for both.
Do you 11 & 12 with great concentration & keep yourself updated.
Good luck!!