Like powder, wouldn't mind a onsie, at home, dabble in thumbsucking (every so often...), use creams, plastic pants, training pants, diapers & pullups, BUT, I'm all DL, with just a smidgen fantasy of being AB. Can't picture an AB in my position, as an over-the-road truckdriver, responsible for moving 60,000-80,000 lbs of stuff down the freeways at speed. Not that an AB couldn't do it, they just wouldn't be living it the way I do, as a DL. I hide my wearing from all, and can live out my life & job, with no interference from the diaper wearing.
Really, it's in the mindset, as far as I can see. If you tell yourself that you're two, and TRY to believe it, and want to act it nearly always, and want a mommy/daddy to coddle you & protect you, then, chances are, you're likely more AB than DL. If you just love the feel of your diapers, but take them into the adult world, and/or sexual world, then you're probably closer to a DL, regardless of when it started in your life.
My life in diapers started just beyond 2 yrs of age, so it's not when it begins that makes the person AB vs. DL, it's more what you do with it, once it settles into your pee brain. In my case, the diapers merged with my personality at a very young age, and though I grappled with it (guiltily) for a long time, eventually I realized the benefit of coming to terms with it, and I began to really love it, which I really do, and have now, for over 50 years. My wife hates it when I say it, but I really believe my first girlfriend was my Gerber's. I loved them. They loved me. They pleased me. Eventually, we grew apart, but I'll never forget those days, and I shouldn't have to. They did no harm, and I had friends that were out gang banging skanky chicks, while I slid around in my plastic pants, humping my bed as my girlfriend, without the risk of lifelong STD's (herpes, syphilis, etc), pregnancies, etc. Of that, my wife should be happy...
Honestly, though, I don't see why a person can't blend in between both worlds, if that's what floats their boat. We're all adults, experimenting with what feels good in life. If it feels good, then do it! If wearing does it for you, kudos, you're probably a DL. If you need all the pacis, the bottles, the crib, the high chair, the kid-printed plastic pants, etc, they you're probably more an AB.
But, if someone (meaning my wife...) took me on a little fantasy trip, heading me into AB land (with some of the above mentions), chances are, I wouldn't fight it, but would just see where it landed me/us. In reality, with my size & weight, and a very hairy set of arms & legs, I/she just have a hard time envisioning me as a baby, though I can really try to think my way into the mindset, if I try real hard & the scen is set properly. Trouble is, she still struggles with a role as a mommy, and I can't force her to like that. so, we can play, but I just can't live it fulltime, the way some AB's tend to do.