There's the option of letting her notice, which that ship has probably already sailed!!
When I got Sober I didn't tell any of my close family, those were the ones genuinely worried about my drinking and used to comment on it, but rather than any announcement, I went a month, then 6 months and after a year they'd seen me at Xmas, New Years, Birthdays, Weddings, a whole range of events not drinking.
The proof was in what I was doing (or not as the case was with drinking) and I remember one of my family mentioning you don't seem to drink anymore, I'm happy for you, there was no question as to why, just a genuine (probably relief) comment.
I'm sure she already has noticed or spotted something is different this time, family were great at noticing our drinking, so they're in a great position to notice our Sobriety!!
