I want to come out to my mom as a bisexual. But I'm afraid she will either do two things 1) Not believe me 2) Ask me why I'm making such a big deal about it its like I imagine it me sitting her down and telling her I'm Bisexual, and she just simply replying "Okay. Why'd you make it a big deal?" Is it a big deal?!
Well if she doesn't believe you, she'll figure it out soon enough a learns she can't tell how you feel. And if she does wonder why a big deal was made, then tell her because ___ (insert why it is important to you) IDK (*hug*)
well at least you're being able to understand how your mother would react. 1) if she doesn't believe you, then she can either be in shock and not willing to accept it or she just needs time to process it. it could mean a lot of things, or maybe considering your age, she just might think you're going through another "phase" 2) you can express to her that if you bring home a partner that you're in a serious relationship with, she wouldn't have to worry about having a curve ball being thrown to her. it's not much of a big deal, depends on your views of life.
It is as big of a deal as you make it. People will always have different views on the subject, but if you feel that it's a big deal (and maybe it is, because it's often a fairly hetero-normative world out there), then go ahead and make it a big deal. At the end of the day, it really is just up to you. Good luck