How do i tell my mom i have a boyfriend if im reallynot allowed to?

Im 13, and ive been going out with this guy at skewl for like 3 months. But my mom doesnt know. and he's been wanting me 2 tell her, and i wnat 2 tell her 2 so we can hang out and go to the mall and stuff. but im not allowed to have a boyfriend and i dont want her to be mad, so i wuz thinking about asking her if she met him and approved then i could hang otu with him and stuff, but im sorta scared she'll say no, so how do i ask her??