Good Morning!  
Head canon time!  
Some random facts!  
This is a young, freshly graduated Comet. Dad Comet isn’t as clean shaven and a little scruffier.
 
~Comet Tail was a successful unicorn student at Celestia’s school, in the same classes as Twilight. The two were often paired in projects, though due to Twilight’s distaste to friends, they never hung out much aside from that.
 
~He moved to Ponyville after graduating and was thrilled when his old peer came to live there.
 
~Finding out about his magical talents, Twilight and Starlight invited him to come help out at the school. Twilight found herself subconsciously visiting his classes more and more to “evaluate” his work, staying after the students left to help clean up and test his new magical experiments.
 
~Soon enough the two started dating, and one thing lead to another. After a few years they got married and had Star Swish.