At the age of 13 i started urinating very often and my symptoms advanced now that i was 16 and i start urinating very hard sometimes i have to push to eliminate urine, i urinate very often and i have to sit on the toilet so i can urinate as a boy?

you should see a urologist. He/She will investigate and treat and make you well

This just not sound right for someone so young. Makes me wonder about things you might have been born with, like spina bifida occulta. Suggest you see a urologist as soon as possible. Will likely want some urine tests, to check bladder strength and function. Best not to let this continue to progress any further....