You know that trainers are like that, they try to make you feel comfortable at work, so make sure that she's not only trying to be nice if you want to go further.
About the hair thing, i don't see it as an IOI, i just see it as an IOI when they swing with it or when they fix eye contact with you doing it, otherwise can be just a normal thing.
But ok, try your best but don't put yourself into awkward situations, i don't flirt with my work mates because of that, i don't want to lose my job. And there are some cute ones here that i wouldn't mind to have something with them...
But as i usually say: Work is work, pickup is pickup
