I think I'd like to be turned into a 6-8 year old little girl. Old enough for diapers and other babyish treatment to be very humiliating, but still young enough to not be judged harshly by society. My potty skills would be a bit worse than other girls my age, but not drastically so. If I was careful to use the toilet regularly I'd be able to stay dry at school and only wet my bed about once a week.
I'd be adopted by a couple of lolicons who'd enjoy treating me like a toddler. They'd be very kind, loving and supportive and they'd never do anything that would really hurt me, but they would have total authority over me. They'd decide what clothes I was allowed to wear, what toys I could play with, whether I could use the potty, and pretty much everything else about my life. They'd listen to me and usually take my preferences into consideration, but if they wanted to take me shopping in just a short T-shirt and extra-thick pampers I'd be powerless to stop them.
Sometimes I'd be allowed to act pretty much like a girl of my age, although even then I might still be prohibited from doing certain "big girl" things like wiping myself after going potty or eating with a knife and fork. Sometimes I'd be given big girl panties to wear but told not to use the toilet, then I'd get scolded and changed into diapers in public when I ended up having an accident. Occasionally I might just be diapered, restrained, and made to spend the whole day as a 6 month old baby.