Will i have heavy periods too?

Hello, the question is. My mum has really heavy periods. I'm thirteen. (my mum and my older sister started when they were fourteen) So i think i wll be starting soon, next year. Im really worried that i wiil have heavy periods too. Because my friends has VERY heavy periods, and she has to go to the toilts every hour. it just looks horrible! also what does having your period feel like, is it constant stomach pains and cramps? and how do you know that it's started. do you feel the blood coming out - i know that sounds weird. but i;m worried i am going to start at scool, and it will be realyy embarasing. thank you in advance to everyone who answers. and please no stupid and silly comments. Thank you. :) :) :) :) xxxx