Am I emotionally undeveloped?

I can’t let go on my anger. I bottle it up and I’ve been bottling it up for so long. I’m 21 and I’ve been angry at people since I was 15 but never said anything. It usually would go away but recently my angry and year long grudges keep bubbling up. The stress is slowly killing me. My sleeping habits are awful, I’m gaining weight, I just feel like crying all the time or screaming or breaking something, and I just don’t know what to do. There are people I’m mad at from like three years ago and I want nothing more then to yell at them and tell them everything they did to mess up me because they were an emotional abuse I’ve jerk. And now, I’m mad at my mom. I’ve been angry at my mom since I was old enough to realize how immature and hypocritical she is but I can’t say anything to her! Literally, the last time I tried to kindly tell her why I was upset with her, she said that because she’s my mother and sacrificed her life for me and gave me food and a house to live in, I need to bite my tongue about everything. Meaning I have no right to be upset at her about anything ever for the rest of my life. I’m grateful for her and my childhood, she was a good mom, but she’s not perfect and human emotions don’t work that way. You can’t just forever never get upset at someone especially someone like my mom.

My entire family is strange. We just like get along because we are blood related to seems like. Like we are forced to be near each other but in reality, we all find emotional support and happiness in other people. My sister, me, and my mom all find emotional support through friendships. It’s strange, like we are all unattached from each other. Like my father for instance has always been in my life and he’s worked hard to give my family a home and stuff. But even though I’ve known him my whole life, I still feel like I don’t know him. He’s very quiet and to himself, he works most of the time so I never really see him, and it’s one of those things where he feels like a really close acquaintance rather then my father. And my mom and I used to be really close when I was younger but when I grew up and moved out, I learned things about her and about myself that I wouldn’t if I still lived with her. Like I got start thinking for myself which I couldn’t do at home because everyone is closed minded and if it’s not their opinion, it’s the wrong opinion.

Point is, now that I’ve been away, there’s so many things my mother does that bothers me. And I can never say anything because shes so unbelievable stubborn and petty and worst of all, she’s a professional victim. She never takes responsibility for her actions and every time someone confronts her about it, she gaslights them. I’m just so mad at her and my ex boyfriend (who was the emotionally abusive person who messed me up) and they are both people I can never confront. Honestly, I never learned how to forgive and I still don’t know how. I grew up in a household full of grudges, being petty and stubborn, and it’s always someone else’s fault. My parents never taught me how to forgive and trust me, that’s someone that is taught not naturally born into you. But now I have to find out how becayse if i could just forgive these people, maybe my pent up anger will go away and I won’t be so emotional all the time. Part of me also thinks it’s because I’m young still and not fully emotionally developed yet.