How Twilight will look in good ol ‘Petalverse’ ;)
 
She’s a lot older now and has been retired for quite some time.  
Her castle in ponyville is where she and her family live now.  
You can find her in the castles library wasting away the hours and harassing her grandson to sit with her and have some tea.  
Her grandson Prince Emerald Star has always been a bit ill. So Twilights always been overprotective of him even if he’s a grown stallion with a wife and foal.  
Once she finds out her great granddaughter is having doubts with the title of princess of friendship she makes it her duty to convince her otherwise.  
A.K.A whip out the books and encyclopedias.