Late bloomers mean u keep growing till 21 and what about others and normally puberty hits in 14 and it happen me also so will i grow till 21?

Hard to say: The period of growth can be as short as 3 years or as long as 7. The defining issue for additional linear growth is having growth centers in the long bones that remain open.An x-ray of your hand can be analysed for the growth centers and how much more time you have can be predicted. If your growth centers begin to close or are closed, you are done. It doesn't matter is you started later or not.

See below: Puberty in boys starts with enlargement of testicles & penis followed by pubic hair at age 9-11, hit growth spurt at average age13.8 years. Growth generally stops by age 18. Late bloomer whose puberty does not start until age 14 or later may grow even after age 18.