mom found out i’m sexually active and i need advice

my mom found out that me (21) and my bf (23) are sexually active. she wants me to get an iud, because my grandma and my mom were both super fertile and apparently it’s hereditary. my grandparents used condoms and fertility tracking but still ended up with 8 children. my mom had me while on birth control and a few years later missed 2 days of it and had my sisters (twins).

i am not super comfortable with getting an iud but my periods are horrible and i have dysmenorrhea. i am getting more open to the idea but what should i know before getting it? i’m honestly kinda worried ngl