you will cover that later when your a little older,
you will then know how to make a hull,
its not really easy and the fact that you have made a nice shaped hull is already brilliant
try different techniques and if you want go through some videos are ask your tech-design teacher at school about how to make one, they will surely teach you some of their techniques
because here on internet there arent many good videos or tutorials about how to make a hull so the closest you could ask first is your own design teacher (a tech one) if he/she doesnt know then ask them how to make a nice curve or round shapes, that might help you on making a hull