About their age difference, here's what I think. As the drama shows, in 2013, Wei Qian's about to attend college, so he's probably 18? And Xian Yuan got into high school early, so he's 13-14? So their age gap may be 5-4 years. Idk man this is what is think. I could be completely wrong
"P'Kang, Don't let go of my hand"
PlsðŸ˜ðŸ˜