Why do girls not just tell me they don’t like me instead of leaving me on read or delivered are they still that immature in high school

I’m talking to this girl as of recently and I thought me and her had like a nice thing I liked talking to her and to me it looked like she had a nice thing talking to me so I build up my confidence and ask her for her number she says yes for the first day we’re trying to get to know each other and I thought it was getting better after telling her I liked listing to the smiths and she’s like “omg I like them to” so I’m like great we both like the smiths and we talk for hours then the next day it’s a little slow but we still talk for hours and when I see her at school we also talk for a good period and laugh a lot in my English class and now it’s Friday I start texting her it usually takes her a few hours to replay so I’m not wondering if she ghosted me or not she replies talking about the padres game and it was on and off a message around every 20 minutes then it starts to pick up she gives me her other socials and then I’m thinking maybe I should ask her to hang out at lunch I do that near the end of the day and she tells me her friends yell at her if she’s not at lunch and I’m like okay that’s fine I didn’t really think anything of it then I text her if she’s free to hangout after school maybe she leaves me on delivered for about 3 days she says she’s not free because of cheer practice and I ask her if she’s free any other day of the week and I’ve been delivered for 2 days and I’m honestly thinking of just leaving her be because it clearly seems she doesn’t like me as I like her or even a friend I don’t mind that the only thing I mind is that I want her to tell me that I don’t like wasting my time on people for no reason

Edit: forgot to put this part in is there any chance near the end of highschool they maybe grow out of this stage because I feel like I can’t even talk to a girl one on one near her freinds