I just turned 18 & I want a later curfew !?

hey everyone, I just turned 18 2-3 weeks ago & I really want a later curfew . ok so my curfew now is 11pm on the weekends & 10 on the weekdays during the summer . i have a car & everything so i control how i get to places & how i get home . & also my parents make me take my little brother every time i go to my boyfriends' house, which is annoying because my brother doesn't want to go & it's weird cause my bf doesn't want to see my bro he wants to see me . but my bf's mom is barely ever home, but still i'm 18 years old & i'm old enough & smart enough to know what not to do & most of the time we dn't sit at his house anyway we'll go out & do something . & all of my friends get to stay out until atleast 1 or 2 & i think because i'm now 18 i should be able to stay out that late, too . but my parents are holding me back with my curfew & having to take my brother with me ... so my question is what can i do to get a later curfew & to keep from taking my bro everywhere with me ? thanks in advance !