Any advice on how to thread this friendship?

Hi, I'm a 20 year old college student who struggles with low self esteem, people pleasing tendencies and speaking up for myself.

I decided I'm going to be better, to speak my mind, to Change and place boundaries. It's been hard, sometimes I stammer when I try to talk to someone about how I didn't like what they did and if they wouldn't do it again, it's really been uncomfortable to voice my mind or to stop people pleasing like now when I'm in a conversation with people and there's silence, I don't try to fill up the silence and although it's uncomfortable because it feels like I failed to keep the conversation going I still do it either way.

I'm reading a book on low self esteem and I'm trying to accept the fact that doing much things for people won't get you to be loved by them and so I'm trying to accept being lonely. It's been hard to communicate and it's even harder to say no, I haven't been able to fully turn someone down yet but now I can say no to things like "no, I can't lend you my pen" or "no I can't play this game with you" and i know it might sound insignificant but I'd like to believe there's a difference, I'd like to believe I'm changing.

Where was I getting to with this? Oh yes, so I have this friend/roommate and I don't like how she speaks to me like for example I tried something by stop wearing my signature cloth and she told me that it was bad and why did I try that? And at first I didn't think about it much although her words pained me, my other roommates even told her that she was being silly and one of my roommates told me I need to put some distance between I and her because she talks without filters and has no boundaries. Sometimes she'd speak for me when talking to people when people ask me to stand up for myself and she'd reply with "she can't, it's not just her" I understand that I do blabber a lot to her about my problems and life and what not but sometimes what she says hurts and she's always acting like she knows me best and speaks for me like it's my thoughts and I never really saw it as a problem but when she says those things, it feels like I'm not changing.

I'm sorry if this is long but I feel bad and I just wanted an outlet coz no one ever gets it. I don't want to hate her because she can be a good friend when I need but her words cut me into pieces and I think I'm having resentment and now I'm doubting myself if I can change or even tell her how I feel about this ... Sigh.