My girlfriend, who is 18, seems emotionally distant after we were intimate, and I’m looking for advice on how to address this.

The phrase "emotionally muted" might sound harsh and insensitive, but I couldn't find a better way to express it succinctly, so I hope you understand. I’m an 18-year-old male, and my girlfriend, also 18, and I have been together for 11 months. This is our first relationship for both of us, and we have each other’s first experiences. For about three months (after being together for eight), we were dry humping, which started accidentally while we were making out. Recently, we decided we were ready to take the next step. We had initial conversations about it while we continued dry humping, but then we talked more intensively for about a week, which probably wasn’t enough time. Eventually, we both agreed that we were “ready,” and the day came when we went through with it. Afterward, my girlfriend expressed that she felt we should have discussed it longer. This led to her feeling hesitant about it and experiencing a sense of "emptiness" afterward. It’s affected her emotionally; her willingness to engage in conversation with me or others diminishes after half an hour to an hour. She seems to force her laughter and often questions her reasons for laughing, feeling like she "still enjoys doing things with me, but it’s muted." In her words, her emotions feel muted by about 80%, making it difficult for her to genuinely enjoy our relationship. I’ve tried to express my love and offer comfort, but she often claims she doesn’t know what’s wrong, and nothing I do seems to make her happy. She reassures me that she loves me, but I can’t help but wonder if that love has turned into mere attachment. She mentioned she doesn’t know what’s causing this and that time won’t heal it, which is incredibly tough because I feel lost (though there was a slight development two days ago). Two days ago, we began apologizing to each other for being intimate. I never intended to hurt her, but with no clear solution, I suggested we take some time apart (not a break—this isn’t something we do). I thought that stepping back might give her the space she needs to understand her feelings without my constant presence distracting her from finding the underlying truth. During our conversation, she mentioned that one possible reason for her feelings might be her sadness about not having hobbies and needing happiness outside of our relationship. She also shared that she had seen videos about boyfriends becoming emotionally distant, which made her worry about signs of that in our relationship. However, these reasons are just possibilities, and she hadn’t communicated any of this to me until now, which left me without the chance to help. As we discussed it, she grew frustrated and decided to end the conversation, asking me to stop and saying goodnight. It’s been two days since, and when I checked in, she only responded with a thumbs-up, which makes me sad because she isn’t open to talking. Additionally, she turned off her location, which adds to my concern. Does anyone have insights into what might be happening with her, similar experiences, or advice on how I can help improve this situation? I don’t want to see her as an emotional shell, as it's impacting our relationship, and I’m determined not to give up on us. **TL;DR:** Does anyone have advice on how I can support my girlfriend, who seems emotionally disconnected?