'Grooming' can mean a lot of things, so I'm not sure it's not that useful unless that's defined tbh, and it's a highly emotive term too.
I do have some sympathy with the possibility that she was vulnerable to that though, but I have no idea how much that was a factor in her case. She obviously had some level of agency and choice though, and yes, while the IS recruiters will present the idealized situation of where she was heading to, she also can't have been in any way ignorant of what was going on there. And some of her post capture interviews back that up, as do some of the reports of what she did when she was there. She didn't exactly spend the time cowering in the family home did she?
Do you think the age of criminal responsibility is wrong then, and it should be raised?
I've met a few male IS fighters, all of whom were as thick as two short planks, and probably by some definitions were a bit vulnerable, and were probably in the position there were in though a mix of factors including (for some) bad luck, ideological choices, religious belief, being recruited, being poor, etc. But Europeans had to put a lot of effort in to get to Syria back then, which in some ways proves they have more agency and choice than some villager in rural Iraq who ended up joining when IS took control of his area.