I went back to the original work to look up the content related to Chen Xin and his father. In the novel, Chen Xin's father's name isn't given, so here we'll use the one from the comic: Chen Jianjun.
And in the original work, it said that Chen Jianjun became a Title Douluo at sixty-eight, reached level 95 at seventy-eight, level 96 at eighty-eight, and level 97 at one hundred and eight.
The year he turned one hundred and eight, he went to challenge Qian Daoliu and died. At that time, Qian Daoliu was one hundred and twenty. When Qian Daoliu sacrificed himself, he was one hundred and fifty, and Qian Renxue was thirty-five.
So from that, we can conclude that when Qian Daoliu was one hundred and twenty, Qian Renxue was five, and Bibi Dong was twenty-four—she gave birth to Qian Renxue at nineteen.
Right now, Bibi Dong was eleven, Chen Jianjun was ninety-five, Ning Fengzhi was thirty-one, and Chen Xin was over fifty-one.
At present, the Seven Treasure Glazed Tile Sect actually didn't have so-called sect-protecting Douluo, but my setting here was that they had a deep relationship with Chen Xin's Seven Kill Clan.
I borrowed a bit from the official drama version's setting—not the original work—where Chen Xin had an intimate relationship with Ning Fengzhi's older sister, though they never married. So Chen Jianjun, as a Title Douluo, naturally counted as someone protecting the Seven Treasure Glazed Tile Sect. He wasn't considered a sect-protecting Douluo; it was probably more like the relationship between Dugu Bo and Prince Xue Xing in the original work.
The seniority here was a bit messy, but this little author couldn't figure out who the Seven Treasure Glazed Tile Sect's current Title Douluo should be either, so I simply went with this format: