Comments so far seems to be mostly telling you that you are valid, and I would also like to start off by affirming that, but I would also like to try to directly address your question.

Let's say, for the sake of argument, (what? Ben Shapiro doesn't own that phrase) that the behaviour and feelings you describe are not normal for transmascs. What does that mean for you? Is the transmasc label important to you? Would you change things about yourself to confirm to normal transmasc-ness? Or would you try to find a different label? When you describe yourself as a transmasc demiboy, what is it specifically you are trying to convey about your identity?

Whatever you are, or want to be, is valid, and I guarantee there's a bunch of people who will feel a similar way. Between "he/him lesbians" and "afab femboys" etc. there's a whole world of people who probably have similar feelings, and if you are feeling some conflict between your own identity and the transmasc label, maybe it's just a case of trying a slightly different label? Or just describe yourself as transmasc anyway if you want to? No one said you have to be normal.