She is a grown woman able to make her own judgements, regardless of your views about them, so treat her as such.
@AclowncalledAlice Age and wisdom do not always go hand in hand.
And it's not the OP's opinion actually.
It's a keeping-safe strategy for OLD, which all the better websites have on their sites as a guide.
In case you aren't aware yourself, these safety tips for a first/ few dates include
-always meeting in a public place
-letting a friend know where you are
-calling them to let them know you are safe (ideally by an agreed time) and possibly when you come home
-being able to make your own way there and back (not accepting a lift by a stranger you have known for a few hours)
-not drinking so much that your decision-making and safety is jeopardised.
-not inviting your date to your home, initially, or going back to their place.
The OP describes how her mum has ignored most of these so far (wit previous dates and clearly this latest one.)
Someone needs to 'have a word' and if it's not the OP then one of her Mum's friends.