How do i tell my parents that i have a boyfriend, and convince them to let me date?

my parents wont allow me to have a boyfriend. im 15, i already have a boyfriend without them knowing and i just cant keep lying anymore because im running out of excuses to where im going and he really wants to meet my parents. how do i tell my parents that i have a boyfriend. and HOW DO I CONVINCE THEM TO LET ME HAVE A BOYFRIEND ???? i am mature enough to date. how do i convince them?