I think it is ok to change your opinion but she has gone on record numerous times talking about how accepting she now is of her body etc. She quotes herself as an ED survivor and there have been a fair few people in her comments who follow her every word, people who have opened up about their ED experiences. Imagine how they feel now to realise the whole body positive stuff is a bit of a sham for content.English isn't my first language therefore I may haven't chosen the right words.
To answer your question...
Anna obviously doesn't like the loose skin on her belly and her "saggy boobs" so I can totally understand her considering plastic surgery to have it fixed.
I also think it is okay to change ones opinion so I don't judge her in this department.
I think she can do what she wants (and she will) but it screams out that she still has unresolved issues with her body and is far from recovered.
I've always found her 'recovery' posts to be quite disturbing tbh because there are very vulnerable people out there and she gives the impression that all you have to do is eat intuitively and love your body, whilst doing the exact opposite in her vlogs (excluding food groups, weight cycling and now talking about plastic surgery for areas she's not actually body positive about).
Ps, your English is fine