18M and 19F. Her mom is making her leave me what can I do?

Been courting her for about 8 months and been dating for 3 months(haven't met her mom in this period yet), but for valentine's I got her flowers and chocolate which her mother saw and got angry at for, asking where it came from and demanding her to stop communication with me after finding out I gave it, also my gf really loves her mom and we only just turned 18 and 19 so we're still reliant on our parents,

so she did obey her mother. what can I say or do for her mother to let me continue dating my girlfriend (p.s she's VERY strict)

also should this be on r/teenage relationships?

im not under 18, but i did just turn 18, prolly not right?