Girl help pls

I’m a super introverted person and have never dated anyone before first of all. I recently started talking with this girl, she’s real sweet and I started to really like her which I’ve never really done before! After while of flirting and chatting she has started to reply to my txts so slowly and leaves me on read all the time, then this morning I woke up to her sent me a picture of herself covered in hickeys what does this mean and why would she send it to me!! Maybe I’m missing something here but is she just not interested anymore?