The thing with romantic orientations, especially when it comes to aromanticism and demiromanticism, is that they’re defined in different ways by different people. Some may develop crushes but still regard themselves as aromantic (maybe because it’s a rare occurrence for them, or such feelings are typically short lived, etc.), whereas others may conclude they are demiromantic, no matter how rare or fleeting their crushes are.
Crushes too, can be quite tricky to define, what is a crush to someone may not be to someone else. Do your crushes feel romantic (in the sense that you really couldn’t describe it any other way, maybe because it’s unlike anything else you’ve felt), or are they more platonic, like feelings of kinship or admiration. The distinction can be very difficult to make and is really only something you alone can know, since it is personal and individual to you.
Your identity is yours to decide, if you think demiromantic better describes your romantic orientation then use it, but if you feel more at home with aromanticism and regard your crushes as nothing of significance then don’t feel obliged to describe yourself differently.