Mom is 35 years old, Xiao Pang 10 years old. Three years later, Xiao Pang was several years younger than her mother.
25 years old. When mom is 35 years old and Xiao Pang 10 years old, the age gap between mom and Xiao Pang is 25 years old, Xiao Pang is 25 years younger than mom, and when mom grows one year, Xiao Pang will grow one year. The age gap is fixed and will not change with age, so after three years, Xiao Pang is 25 years younger than his mother.