Thanks for being open to asks. Recently it's become quite clear that I'm ace. I'm pretty sure I'm not aro. I've had maybe two or three "crushes" in my 25 years, more like a want to be near and spend a lot of time with someone. Still it's something that happens rarely and passes quickly. What's hardest for me is trying to figure out how to explain it to allos. I feel usually get the "you just haven't found the Right One" speech which is frustrating. Any suggestions?
oh man, I so feel you friend.  Whenever I’ve tried to explain being demisexual to my friends or family, they’ve reacted with ‘I think that’s normal!’ and it’s like ‘well, judging from how the rest of the world/you behave, I don’t think it’s just ‘normal’, can you not?’
(to be fair, I’m pretty sure my mom is also demisexual/gray-ace, based on conversations I’ve had with her over the years, but she doesn’t have the vocabulary to describe this? so I guess to her, me describing her own experience would, in fact, seem ‘normal’.)
Unfortunately, I’m not sure how to get around the many allosexual-splanations of why you can’t possibly be not attracted to anybody. I’ve always just let the subject drop - but I’m also a bit of a social wimp.
For explaining what asexuality is, here’s a couple of ideas:
start with a statistic.  ’1% of people don’t experience sexual attraction, and I’m in that 1%.’  People have a harder time arguing with numbers - it’s scientific, after all.
don’t try to explain it from your perspective: try to explain it from theirs.  For instance, if they’re straight, tell them it’s just like how they feel when they see someone of the same sex that could be considered sexually attractive: you can appreciate how they look, but it’s not a turn-on.
point out you’re not broken and you’re not looking for them to fix you.  When people try to explain to you why you’re wrong about who you are, tell them straight out: you’re not looking for them to ‘fix your problem’ or reassure you that someday, you will find true allosexual love!  You’re just telling them how you feel about things, and you want them to respect it as they would other sexual orientations.
Most people who are arguing with you about your orientation are probably doing it out of concern, because many people belabor mistakenly under the idea that ace people are ‘missing out’ on all the fun of sexual attraction.  They want to reassure you that you’re normal, and that’s a very kind thing to do, but they’re going about it in horribly wrong ways.
The people who aren’t doing it out of concern for you are probably arguing with you because they feel threatened - the idea that some people aren’t experiencing sexual attraction seems to be pretty scary for some people. They’re probably going to give you every cliche ‘allo-splanation’ for why you’re Totally Not Asexual and how Asexuality Isn’t Even a Thing - and there’s really nothing to do but say, ‘no, you’re wrong,’ and repeat yourself until you’re tired of it.  You don’t have to argue with these people - there are tons of resources online for this these days.  I’d end a conversation like this with ‘look it up!’ if they persist too long, and save yourself the headache!
I hope this helps you a bit!  I haven’t tried these techniques myself for the most part, so I don’t know if they’ll be super helpful, but this is what I’ve observed is most helpful from reading online and what people have said to me - and are things I wish I’ve said myself, haha.  ;A;