how old are we talking about? because if she's 16ish or older than YDI. Let her spread her wings a little and she wouldn't have to hide stuff from you

Following your daughter around is really creepy. Will you be passive aggressively threatening to her future boyfriends too? She's going to cut you out of her life when she's an adult.

You could try to play the card that protecting her is your top priority. If she's 12 or dating someone who is completely inappropriate, that might fly. Otherwise, you're just a nosy creep.

If I were you, I would have a good long think about why exactly your daughter felt that she had to keep that secret at all costs.

If she feels like she has to hide something as benign as a date, then you done fucked up somewhere.

You were expecting us to side with you? Fuck off and let her live her life. And get one for yourself while you're at it.