Do not send him nudes. He is a horny teenage boy who just wants sex. He will show all his little friends your nudes and you'll be a joke of the school and labelled a whore. He is not someone who cares about you, I know at 14 yrs old it is hard for you to see...but someone who is interested in you for you, and not for easy sex does not do what this little shit is doing.
Once you send someone those kind of explicit pictures, they are out there FOREVER. And one day when you're 30, it will matter. Be smart and don't buy into horny teenage boy charm or peer pressure.