I'm an 18-year-old girl in love with another girl who is also 18. We have five months until graduation. I need some advice.

I've never posted on Reddit before, so if my explanation isn’t clear or if I miss something, I apologize—I'm a bit lost here. About a year and a half ago, I met this girl, let’s call her Ash, when I started at my current high school. To me, Ash is the most beautiful girl I've ever seen. I was a bit nervous and trying to make friends, so I ended up talking her ear off with random chatter and silly jokes. At first, she was pretty quiet, and I felt bad for making her sit through my cringy puns, but she would giggle at them, and it was the cutest sound ever. Eventually, I settled into a friend group while still having plenty of classes with Ash, where I always ended up sitting next to her. She has the most beautiful eyes, and I felt myself melting whenever she looked at me. We had a great dynamic, at least in my view; our senses of humor aligned, though she was more reserved while I’m fairly outgoing (or at least I try to be). We bonded over our favorite TV shows and music artists, but in our own unique ways, like two puzzle pieces fitting together. I recognized that I had a huge crush on her fairly early on, about a month after starting at school, but I was hesitant to address it. You know the classic fear of ruining a friendship and feeling scared? Plus, I’m pretty young and haven't had much romantic experience—especially with girls. I've had a few crushes and made out with a couple of girls, but I always chickened out when it came to confessing. This crush feels different; I genuinely want to spend time with Ash. It frustrates me when she’s critical of herself and makes self-deprecating jokes because, honestly, she's my dream girl. Fast forward a few months, and we became close friends at school, though we never hung out outside of it. I met this guy, who I'll refer to as Malakai, through a mutual friend, and we hit it off. I did like Malakai, but every time I was around Ash, it only reminded me of my feelings for her. That made me feel guilty since Malakai and I eventually began dating, marking my first real relationship. I would share updates about my relationship with Ash, which was awkward given my feelings for her. I think I did it to downplay my crush and make her think I wasn’t interested in her. Six months later, I broke up with Malakai over the summer before our senior year because I found out he had beliefs I couldn’t align with. To be honest, I wasn’t upset about the breakup. When senior year began, everything felt different with Ash. We hung out outside of school for the first time, and I tried to gauge whether she might be into girls. I mentioned that I’m bi, and she replied, "Me too." I nearly screamed inside! It felt like our interactions became more flirty. I started resting my leg on her lap during class, and one time, she gently touched my foot, which sent shivers through me. She began brushing hair from my face and holding my fingers when we talked. I genuinely can’t tell if she’s flirting or if I’m just reading too much into it and that’s her way of interacting with her friends. I really care about Ash, as a friend, as an incredible artist, and as a woman. I don’t want to have to live with “what ifs” in my head forever, but I’m also afraid to make her uncomfortable or ruin our friendship. If she has similar feelings, I don't think she'd voice them because she's more soft-spoken and may struggle with social anxiety. If there’s any hope for something more, I know it’s on me to figure it out. The issue is... I’m scared. What would I even say? Maybe something like, "Love your makeup today, Ash—oh, and by the way, I’m totally into you, but it’s cool if you’re not! Where did you get that lip liner?" We’re graduating in about five months. I’ll be heading off to university abroad, and she’s planning a gap year to travel. I’m asking Reddit because my friends are a bit odd and I feel they would exaggerate a wlw situation, and I’d rather keep it private. The few friends I trust have told me to just go for it and tell her how I feel, but I need more detailed advice, and I'm too scared to ask. If anyone has any wisdom to share as an experienced lesbian or just someone who's been through something similar, I’d really appreciate your insight. Thanks for listening to my thoughts! TL;DR: Bi girl in high school, graduating in five months, unsure how to confess feelings to another bi girl. Seeking advice.