How to create a birthday calculator

#include<stdio.h>

main()

{

int pd,pm,py,od,om,oy,nd,nm,ny;

printf("enter the present date example-30 12 2000\n ");

scanf("%d%d%d",&pd,&pm,&py);

printf("enter the date of birth example-\n ");

scanf("%d%d%d",&od,&om,&oy);

if(pd>=od && pm>=om && py>oy)

{

nd=pd-od;

nm=pm-om;

ny=py-oy;

printf("your age is\n years=%d\n months= %d\n days=%d\n",ny,nm,nd);

}

else if(pd<od && pm>om && py>oy)

{

nd=(pd+30)-od;

nm=pm-(om+1);

ny=py-oy;

printf("your age is\n years=%d\n months= %d\n days=%d\n",ny,nm,nd);

}

else if(pd<od && pm==om && py>oy)

{

nd=(pd+30)-od;

nm=(pm+12)-(om+1);

ny=py-(oy+1);

printf("your age is\n years=%d\n months= %d\n days=%d\n",ny,nm,nd);

}

else if(pd<od && pm<om && py>oy)

{

nd=(pd+30)-od;

nm=(pm+12)-(om+1);

ny=py-(oy+1);

printf("your age is\n years=%d\n months= %d\n days=%d\n",ny,nm,nd);

}

else if(pd>od && pm<om && py>oy )

{

nd=pd+od;

nm=(pm+12)-om;

ny=py-(oy+1);

printf("your age is\n years=%d\n months= %d\n days=%d\n",ny,nm,nd);

}

else if(py<oy)

printf("invalid your input    \n INPUT AGAIN");

if(ny>13 && ny<20)

printf("Ohh u r a teen ager");

}