After the Sacred Tree Appeared, I Saw My Dead Crush

I had a crush on Lu Chuan for six years. He passed away on his 21st birthday. It was also on that day that I found out that he had also liked me for six years. In order to see him, I traveled through time and space. At this time, I was twenty-one years old, but there was a child who insisted on calling me grandma, but Lu Chuan always looked like he was fifteen years old.