ok so i don't do diy so i can't speak to the rest, but you'll for sure be able to hide it (assuming you hide the hrt itself) for probably 6 months at least. past then it depends on how your body develops and how much you can get away with hiding it. i'm 3 years on hrt and could probably still boymode around people who knew me if i stuck entirely to baggy clothes but it'd be hard. my gf could absolutely not. it all depends