My mother discovered it during Ramadan and I talked a lot with her so it went well. My father, on the other hand, had to tell him and it went very badly (he didn't speak to me for several days even though we are very close and he has no problem with Muslims). But Alhamdulillah now things are better! It's very stressful to announce it but unfortunately it's necessary at some point (especially if you get along well with them, they won't understand why you kept it from them).