Nice to have you on the forum.
Beautiful snake.
Looking at the photo you posted I don't see the usual scale spread seen on gravid snakes.
It might be possible the baby delivered was the last of the litter and that she delivered before she was caught.
Here's a link to the care sheet. Baby care is the same as adult care with a few exceptions. Babies require much smaller food and should be fed more often.
A good shallow water supply is needed as babies can dehydrate easily.
Garter Snake Care Sheet - Caresheets

Any questions not answered in the care sheet can be posted to the forum.