13yo dd Always cold - Causes ?

[Flossiefoo]

DD has had a full blood test but everything satisfactory.
She's frequently cold and wears a hoody (if she can get away with it) in hot weather.
The car was 29 degrees this week and I had to force her to take her hoody off. She said she felt fine.
She'll shower and in the evening and then put a fleece onesie on.

Although her bloods show nothing untoward I am just wondering if anything undetected could be going on. She gets quite tired too.

Is she very thin? What is her BMI?
Mind you, I have a teenage son who will happily wear a hoody in extremely warm weather.

I always wear two layers and have been mocked for wearing a cardigan to the beach in Spain. I think some people just feel generally colder, especially if quite slim.

Is she eating enough/properly? Presumably bloods would have picked up any concerns iron/vitamins-wise.