DD1 is 17, 18 in a few months, and in Y13 doing A levels.
She's always had a bunch of different friendship groups and has often gone out with friends once or twice a week but then had periods where she's not gone out much at all.
Suddenly she's made a new friend from work and she spends ALL her time with her and is out almost every night after school.
This girl is not at the same school as DD's and seems to be out of school more than DD1. She is always available to drive DD around and picks her up from school and drops her home after they have been 'studying' together. We live a good 20 mins from the school, so it's not like it's just around the corner.
DD wants to stay over at her place at least once during the weekend and then goes back to hers after work/ school. She's going to parties with her and basically spending every spare minute she can with this girl.
And then every night after school she is 'studying' in the library, going out to eat, and not coming home until10/ 11pm at night.
The girl seems nice enough and I have her address, so I do know where DD is supposedly spending the night when she stays over, but it's such a behaviour change for DD that I can't help think something is up.
She doesn't seem drunk when she comes home from parties ( she has in the past), she says she wouldn't touch drugs, I've asked if a boy is involved and she says no, and her friend has a boyfriend so I don't think it's anything between the girls, but maybe...
Also, DD has lied to us a few times about how she's got home-saying she's walked/ taken public transport when this girl has given her a lift. I've never caught her lying before so that's not helped me trust what she says :(
I know she's almost an adult and up until now she's done well academically, but it's such a change in behaviour.
I'm worried but maybe I'm being over protective?
What do you think?