Why doesn't my mom trust me?

I'm basically 20. I live at home, I work and I graduated school. My boyfriend whom I've been dating for 6 years now is at job corps in Oregon, I haven't seen him for a while and the only time I really get to see him is if my parents bring me. Which I am grateful for! But whenever I bring up catching the greyhound there on my own my mom freaks out at me! My older sister was able to go out on her own anywhere and stay wherever since she was 13, she's 25 now. My brother has been able to go out and do whatever whenever since he was 13 as well. She tells me it's because I'm a girl but that's bs. Her other excuse is I wouldn't have a way to get around but there's Uber, and taxi that I can obviously use. My boyfriend would be with me the whole time too.. I just don't know what to do. She won't let me do anything and it stresses me out! I feel like she suffocates me so much it's effected my personal life, I feel like I can barely take my boyfriends phone calls without her prying into our lives. I feel like most of my anxiety attacks come from her constantly pushing and making me feel like I can't do anything on my own.

UPDATE: I bought a ticket to go see him next weekend 😁 we're going to get a hotel and go explore the town ☺️ ❤️ my moms pissed about it though 😂