@froggy_hoppy Frankly where I live, I have not ever come across LGBTQ+ case probably because I am in contact with a lot less people and due to my state's "not so open minded or rather unexposed to other form of sexual relations" ways. But at personal level I am highly open minded person(in comparison to where I live and my family) so I can only give you little advise that if you have nice relationship with your mom and you are not in any hurry or urgent circumstances then I would say let time work its magic and slowly you can get your mom to view "seriousness" of your relation. I believe that's most important part as it will also give you and your partner time to deepen your bond too if you really wish to be together. This i I would say "typical nagging words" to you that at end don't make rash/hasty decisions when it involves relationship problems. Understand your mom's perspective too and slowly convince her because even though she and I might be open to LGBTQ+ but believe me it will give her quite a big shock/surprise if her daughter is involved in it when she herself or close to her people were not involved in it. Also remember according to her and Society's general perspective opposite sexes attract each other most of times so it is natural for her to think that in your case too, you might change your opinion later. So at end give time even though your relation might also become sour with her seeing your "grit" but at end if she sees you are happy in your life, I personally believe she would understand at one point no matter how long but that's my wish and perspective for you.
That's all for serious talk. All the very best, chill and enjoy. I hope your problems may be resolved and you find happiness.