Sometimes, it is hard for parents to understand this completely as in one hand, they feel like they are losing a daughter or son. Obviously, it is hard for you as well. I think your best bet is to google for local Gender Pathway Services and clinics, and maybe you and your mom can go talk to a specialist. My <AMAB niece> wants to <transition to female>, <s>he is only 13 years old, and as <her> mom is extremely accepting, she is still scared. She is deathly afraid that she will let <her> continue with hormones, or a surgery that could end up hurting <her> (as far as a bad surgery and <s>he dies etc. normal mommy things to worry about lol). So, she initially said she wanted <her> to wait until after he is 18 to do anything like surgery etc. but she also has made an appointment with our local Gender Pathway Clinic to talk about pros and cons of waiting, and she also found out through some researching that there is a lot of things that can happen during puberty that is irreversible and can hinder one's ability to truly be and feel like the person they were meant to be, not the person they were born as. So I would talk to your mom and see if she would be at least willing to go talk to a specialist with you, to at least see the options and pros and cons etc. I hope this helps and doesn't seem like I am telling you what to do. Sometimes I try to hard to help and it comes off overbearing.
Moderator edit: our site accepts and prefers to use the gender that is identified. I don't think you were trying to show disrespect but it sometimes upsets people. I have edited some pronouns and a sentence or two.