So, first of all, you're fine. Even if you later decide the demi label doesn't accurately fit you, trying it on now and testing it out is way more worthy of respect and IMO healthier than going through your live not examining yourself carefully. Trying to figure out how you work is worthy, even if later you decide your hypothesis right now didn't hit the mark.

As for the hate on demis, so far the only hate that I've seen is coming from casual online communities, random people on the internet. If mental health doctors, therapists, board-certified sexologists were on the record saying that demisexuality isn't a healthy way to self-identify, then that would be one thing, but we haven't seen even a bit of that as far as I've heard. All the anti-demi attitude has been coming from people who aren't informed by research or personal experience, and it comes down to little more than "I don't like considering that people like who you say you are really exist!" Anti-demi attitudes aren't actually statements on demisexuality, they're more like attempts to keep simple notions of sexuality from being expanded into anything more complex or variable.

So welcome! Good luck on the quest!