For me, very few know, however of the few I've told all have gone surprisingly well.
I have a close friend I met online back in middle school who knows and was actually the first person I talked to about it after he opened up about his fetishes. We did some roleplay for fun in high school, and after bringing up some ABDL themes in it I thought it was something I should bring up. I brought up the topic, said I was into it, and he was actually pretty curious. A bit of a tangent but I brought up how to fold towels to make a sorta makeshift prefold diaper and turns out he liked it enough to continue for a while. After high school, things tamed down and I think he kinda gave up on the kink after getting nervous about being associated with pedophilia, which is understandable. We still talk about kinks and stuff, though just whenever the subject comes up.
Another friend I told was actually a classmate of mine in high school. We met freshman year and got along pretty well. Fast-forward and we're about to graduate and head off to college. We had a small friend group of geeks and nerds and decided to do a pretty personal game of never have I ever. It was the last year and we probably wouldn't see each other again so what the heck, right? All is going well until my friend fesses to having a kink for pet play. While I'm not into it, it did give me the idea to make a collar for them, which, looking back on it was probably a really weird thing to do. But, they really liked it, and it prompted a conversation about kinks and it eventually came out that we both had a thing for ABDL. It's really uncomfortable to look back on, and I probably was a bit too enthusiastic, even if it was mutual, but it was my first time having someone in real life that I could actually talk to. I haven't heard from them since we graduated, but it was the first few weeks where I didn't feel like I was completely alone with this weird ABDL junk.
Lastly, family so storytime. I should preface by saying that my family is more liberal minded and that there was a reason for telling them. When I was about 13 I was in a very bad car crash. By some miracle my mom and I made it out okay, though the situation left an impact on me mentally. It was the first realization I had that any day I might not be around to see tomorrow. I knew I had these desires in me as far back as I can remember, and at that point more than ever I wanted to at least have a chance to indulge. However, as I was too young to be independent it would mean going behind my parent's back and hiding diapers in the house. It took a few months for me to consider what to do, and most of the advice I found said not to tell family. However, I'm very close with my parents and we had a lot of trust, and I really wanted to keep that trust. I weighed out the costs and benefits and decided it would be the right thing to tell them as long as I'm living under their roof.
I decided to start with my mom since we have the closest relationship. It was probably kinda dumb, but I scheduled a meeting in my room one night to tell her. I was so nervous about it, but I just wanted to get it out. And I did. I told her I like wearing diapers and her immediate reaction was relief of all things. Apparently she'd thought I was doing drugs or something, and hearing that I had a kink for diapers was a hell of a lot better. We had a good talk and I was able to share some resources with her to help explain what I couldn't. I also asked to see a therapist to help, which was also agreed on. The one thing I wanted to make clear though was that I was still the same person and that I wanted to still be treated the same as always. After the talk we agreed that she could tell my dad and brother, though I've never talked to them about it before.
To answer your questions:
-They let me indulge a fair bit, and it's normal to have a pacifier out on my nightstand from time to time, but I try to keep it as personal as possible. I can wear diapers around the house under my regular clothes, though I've mostly stopped doing this.
- As for involving my family in age play, that was a BIG no from the start, and I made sure to establish that. It's my weird thing and I don't want them involved. While I'm incredibly thankful for them, my situation, and how unbelievably well things have gone, I do not want them involved in this part of my life. It's not something they need to be involved in, and all I wanted was understanding and the freedom to indulge on my own.
) when I was in college/grad school/the year after, so I haven’t lived with anyone and worn regularly since high school (and my family probably has no idea as I was very careful). My mom tried to get me to see a therapist in middle school because of unending nausea, but I was terrified they would make me talk about diapers so I never went.
and not just disguised guy. 
