drills used to throw a harder straight right

So i want to throw a harder straight right. But its harder for me to do that because im pretty small
I am 14, although i am only 4 ft. 8 in. and about 80 lbs I am still a begginer but i wanna get really good at boxing. Because i wanna use it as excersise and self defence. I am pretty much still a begginer at boxing. But i can't afford a gym or a bag so i would like to know what drills or workouts i cud use without a bag or a gym to increase my power in my straight right.

Pivot on your right foot. That will turn your hips, then your shoulders. THEN move your right arm and right hand.

You feelin your age mate?