When I was a child, I went out with her friends for the summer vacation and didn't invite me. I feel lost and a little jealous. Has my relationship with her faded away?

This is normal, because you think differently from others. In other people's consideration, maybe his friend is more suitable for this trip together, so there is no need to think too much. As for whether the relationship has faded, it depends on whether you care or not after a long time of contact. After all, everyone has their own circle of friends outside the circle of friends, so just calm down. In addition, we should also reflect, don't rely on our friends unilaterally, but also take the initiative to think about whether we have neglected our friends. Emotions are mutual, and we can only last a long time.