Don't feel stupid for posting. We get to answer, and that makes us feel smart.
Next time I will have a dumn post and you can feel smart straightening me out.
( (I am kinda crooked)
Along with your new mare testing out your worthiness to be her leader, she is probably just plain old scared to go out alone. New place, new leader, all alone, sounds scary to a horse mind.
Go out next time to where you know things will get difficult and turn for home BEFORE she makes the decision to go for home. Or, go kind of a different direction, not away, if that is possible, like parallel to home.
Anyway, I always encourage people to not get into thinking of their horse as being a brat when usually the horse, from his /her equine brain, has a perfectly good reason for doing what he is doing, and it usually isn't to make trouble for you in a bratty way.
Your mare is really cute and I bet step by step she will prove an excellent trail horse, but it doesn't happen overnight.