I think it depends on how you feel towards your body and how people perceive you. Being trans usually means you're unhappy with at least some of your attributes and would like to change. This doesn't have to mean you want to completely transition to the opposite sex, it could also mean, you'd like to change your hair and wear different clothes that closer match your gender. For example, if you're a demigirl and feel uncomfortable wearing a dress or having long hair or wearing girly make-up but in certain situations it is expected of you, I would count that as trans (but good luck explaining this to people who still think there are only two genders).
Now, being a demigirl doesn't mean you have to hate dresses or long hair or whatever. If you're completely comfortable with all of those you're still a demigirl (if you identify with that, which I'm just assuming you are from your meme), just perhaps not trans. There are many different ways of being demigirl and even more ways to express yourself and all of them are correct. The same might apply to being trans, but for me being trans has to do with wanting to change something/wanting to transition. By the same logic, I don't think someone is still trans after they have changed things about themselves and are now completely happy with their body, clothes, etc.
Being cis is a slightly different matter. You could say you are cis as demigirl is still a female gender. You could say you're not cis, because demigirl is different enough from female that you don't feel like being grouped together with "traditional" women represents you. It all comes down to how you feel your gender relates to female and how close or removed you are from it. This is why people who feel trans usually don't feel cis and vice versa, but there is a middle ground where you could feel both or neither as well. Unfortunately, I don't know if there is a word for that but maybe you could come up with one. 😉
Caption this Meme
