Hii!
Yes. Usually class 11th and 12th are considered as school level only and is called higher secondary school. But, in many places it is called college. We usually don't refer to graduation course as class 13th , 14th and 15th, but it is referred as Bachelor's course. These are specialised courses provided by colleges under various universities across the country.
If there's anything else you need to ask, feel free to do so.
Hope this helps.
Good luck!