Oh wow, the god artist for "I Made Friends with the Second Prettiest Girl in My Class" does yuri for their series where they are both writer and artist? What a pleasant surprise.
This start seems fine enough, but it's lacking anything that gets me particularly exicted, and feels a little generic. Hopefully the next few chapters can do more to differentiate it.
I think it's fine. The first one is meant to be an awkward high schooler saying something incredibly cringe while fumbling for what to say so it works well in character. The other two I can't think of better ways of saying off the top of my head. Saying "if only everyone else was half as kind as you" would work probably but it's not a significant improvement. I don't think that this is nearly as bad as your comment makes it out to be.
I really don't know why some people can't comprehend this. Japanese teenagers also use slang, and if they translated all of that slang completely literally, it wouldn't read as slang to english speakers, so substituting english slang better captures the author's intent. It's really not complicated.
Of course I know the real reason you're mad is cause you think those lines sound "woke" or whatever, but even the fake reason you're pretending to be mad about is super dumb too.