Exactly, I personally don't feel she would make a good princess. But that doesn't matter because her journey is different then Twilight's she is the goddess of friendship, while Starlight's path is very mysterious she will likely not ascend and that's okay even for fans because for her to be an Alicorn comes with a new role and responsibilities that would hinder her in her quest for she needs to find out who she is still, she still has much growing to do and may leave a meaningful impact in Equestria beyond what we have seen or may not. Even the smallest deed can lead to a great action and she seems to exemplify this as Twilight's small deed of befriending Starlight as opposed to defeating her has led to Starlight dethroning an evil queen.



There is much to learn for her still and to become a princess would mean that she has mastered the student phase and become a master, though Twilight still struggles it is a different matter all together as it is due to the weight of the world on her shoulders, Starlight cannot and should not take upon that weight but rather help others who are carrying it to slightly lighten there load.