An idea I had. Demigirl help is appreciated!

I'll try to make this short.
Before tonight, I had come across the word demigirl but I didn't really look up for the definition. I did manage to understand that when you are a demigirl(or a demiboy), you are transgender, because your parents didn't look at you and say "this baby is a demigirl or demiboy", they just assumed you were a girl.
I also knew that when you are transgender, you are an oppresed person and you are angry because you are condemned to a life of social reclusion with little possibility of getting out of that situation.
Tonight, I discovered the definition of demigirl and it suits me pretty well.
Other people in my situation would say "ok, demigirl it is!".
Not me.
I refuse to think it is so easy.
And I refuse to call myself transgender when I don't understand how disphoria feels and never really suffered for having to be something I am not. It is almost insulting for other transgender people, from my point of view.
That doesn't mean I haven't questioned my gender before tonight. I actually had a pretty ruff time with the whole subject last year. But in october, I decided that I was a cis girl. The problem seemed to be solved. I still had concerns, however...
But the point is that I hadn't had them until I started researching and knowing about gender identities(that was last year). Before that, I was a girl and nothing could never change that.
So, the idea I had is that I should not consider myself a demigirl, keep saying I am a girl, because I discovered that term at an old age(17/18) and wasn't set in my "system" before and I never doubted it when I was a kid(unlike, for example, a female-to-male identifing person, who seem to be able to notice from a young age that he wasn't what everybody told him to be). I like the idea that gender is not fluid. Isn't it hard to come out and say something like "I am gay/lesbian/trans" just one time? I can't imagine doing it multiple times. It's just not practical. Also, people have lived with just one gender for their whole lives for a long time, and most of them didn't feel the necesity of doubting it.
The only situation in which I would consider to identify myself as a demigirl is if I am not transgender. I am cisgender because a) I don't know how disphoria feels(I know dishporia doesn't define your gender, though), b) I don't think it is just a choice I can make, especially not when I am 18, c) Even if it were a choice, I wouldn't choose being transgender, because it is not practical and you are a misfit in society(at least in my country) and I don't want to voluntary be that.
I am sorry if that last point offends anyone, but... wouldn't you? Isn't it VERY much easier to be cisgender? I would choose the easy way. Or at least, I would choose the way my parents wouldn't send me to therapy/kick me out of the house for.
What do you think? It is possible for a person to be cisgender and demigirl at the same time?
I only want to be at peace with myself, and being demigirl AND cisgender at the same time might help me to.
Not that I think it matters, but if you want to know: I have short hair but I don't really like it, I never wear bijouterie and rarely use any make up. Only foundation(everyday because acne) and lipstick when I think it would look nice.