Well my Little told me after we had known each other one month, or thereabouts. For us I'd say he timed it about right and I appreciate how direct and honest he was about it. The timing was good because it was enough time to get the idea of whether you liked the person but not so long that you had invested so much to risk it being devastating if that person said "um thanks, but no thanks".
Now to be fair, I'm not that vanilla myself, something he deliberately asked me about the first time he met me (why waste effort if the person isn't into kink at all was the thought process). He spent a lot of time figuring out exactly where I lay on the kink side of life myself before he told me about his diapers and baby thing. We have quite a lot of overlap in our thoughts/ kinks/ general outlook even if our preferred scenarios may be a bit different. The whole ABDL thing was new to me - well, I knew it existed I guess but had never, as far as I know, met anyone who is ABDL before. But as I said to him, different is good, I like different. And he was up for doing my preferred scenarios too - so that seemed nice and fair to me. A good fit for each other really. So people like me are out there - you have to just keep looking and be brave enough to give it a try. It will almost certainly take you lots of tries before you find the right fit for you.
You know, I read a lot. And I used to think I HAD to read a book from start to finish. I'd almost torture myself into getting to the end of a book I really wasn't enjoying. You usually know if you don't like a book after a chapter or so. Then someone said to me, why waste your time on something you don't like? If you don't like it, put it down and go read something else. And you know what - dating is like that. Give it a try and be OK with just putting those that don't fit you aside. No need to be mean about it. Just be direct and honest and if they don't fit you, put them down and go try someone else.
Anyway, if I'm honest, back then I didn't really appreciate just how stressful it was for him to tell me at all. Because he was so direct in his questions to me, and so sure of what it was he liked. I assumed he had buckets of confidence about the issue. It was only later when we were talking some more, and after I'd signed up here for some education and support, that I realised how incredibly vulnerable and stressful that conversation had been for him. It's been 6 months now and I can honestly say it's been a rollercoaster BUT it's also been the most open and honest communication I've ever had with anyone in my life. No idea where our relationship is heading but I'm very glad he found me.
I hope you can find your person.