How to tell your mom you know santa doesnt exist?

hi im miss s's cousin hannah. im in 7th grade and i already know since last year that santa doesn't exist (i hear my mom on the phone) so she hasn't told me and last year on christmas day when we went downstairs to open the presents my dad said "and this?(talking about the santa presents)" and my mom said "santa claus presents" and my dad said "still?" saying it like i shouldn't believe in santa anymore but it seems my mom doesn't agree with that. the thing is i want to get the gifts still but i want my mom to tell me the Truth cause i don't want my dad saying the same this year. so what should i do tell my mom to tell me the Truth and that she buys my gifts now (well she did duh) or still "believe" in santa even though my dad may say something like that?