Head Canon time!
Princess Twilight sparkle is the renowned princess of friendship, researcher and scholar of equestria. In my headcannon, she did not become the ruler of equestira (yet?) but she stays as the head-mare at her school of friendship along with her husband Sunburst. Her children also occasionally teach. In addition to teaching friendship, other cultures and creatures are welcome to come and teach as well. In addition, magic is taught to those who may not have been perceived to have wielded it before.
She married Sunburst, past royal crystaller of Flurry Heart. He aids twilight in running the school of friendship and their various branches.
-Not sure if this is in my universe or an AU Overcome with the anxiety and stress to appease princess Luna and Celestia Twilight seeks out the mirror pool that allows ponies to clone themselves if they recite a chant. Blinded by her desperation, Twilight clones herself to alleviate the stress of being the sole ruler of equestria. However, the pool causes the clone to be almost single minded and uses the most exaggerated personality traits of the original recipient. The clone is unpredictable, irritable, snobbish, and constantly in pain. You see, the harmony is shattered. There is a “false alicorn”. A destiny does not have shortcuts. Hopefully, this will be expounded upon more. I’d love to hear more about this!!