TW: mention of abuse/neglect

I (15F) have been with my girlfriend (14F) for over a year now. Not that long, and I know we’re probably pretty young on this subreddit, but I didn’t know where else to go. We’re both in high school, so relationships usually die out anyway. My mum told me to wait until it just fizzles out, but I hate lying to her. We’ve both been through a lot. We both dated the same person once (abusive ex who dated both of us at the same time). And she’s basically my best friend. I’ve recently figured out that I’m aroace (feeling no sexual or romantic attraction to anyone), and I told her that, she’s fine with it, but she just thinks that we’re still dating despite my coming out, because aroace people can still date. We both have childhood trauma, so I’m scared that if I tell her that I want to break up with her, she’ll spiral and I’ll lose her. We both struggle with mental health, and like I said, she’s one of my best friends, so I don’t want to lose her. I just don’t feel attracted to her anymore, and I don’t know if I really did. I hate lying to her, but I’m genuinely too scared to tell her that I don’t like her like that anymore. I know I shouldn’t do it over text, but I hate calling people and I’m a very awkward person, so if I tried telling her in real life, I’d probably chicken out anyway. While being on seeing her irl, I never do. Her dad never lets us hang out. Her dad is pretty neglectful to her and her brother, and me and my mum have called CPS, but nothing ever happens. But that’s a separate issue. Since her dad never lets us see each other, I’d probably never get the time to see her irl to tell her other than holidays and birthdays. I don’t want to lose her as a friend because she’s probably my only real friend at the moment. My mum has asked if I’m sure that I 100% don’t like her like that, and I always respond with „no I don’t like her like that, I see her as a best friend“. Which is true. Sometimes I have to stop and think if I’m just going through something and trying to convince myself that I don’t like her, but then I realise, I don’t like her. I smile at my phone when she texts because she’s the ONLY person who texts me and asks about my day. It’s nice to know that someone actually cares about me for once, and on top of that, she’s genuinely funny. She cares about my feelings and what happened in my day. No one else cares like that. I don’t want to lose her or her to drift away if we break up, because she’s literally my best friend. I think of her as my best friend, not really my girlfriend. I could never distinguish the difference between platonic and romantic attraction for the longest time, but I realised that I don’t like her romantically. We never kiss or do those weird romantic/sexual texting roleplays because we both think those are weird (even though she does want to kiss me irl and has like once but I told her I don’t like it). Any advice on how I could tell her that I don’t like her like that but still want nothing else to change?

Here’s my ballsona! (Also looking for some advice in the body text if that’s okay!)