How can I tell if my freind has turned to Atheism? [Spirituality & Religion]

I'm seeing my friend who has went off to uni and there seems to be subtle changes about her that make me wonder if she still respects Jesus. She still seems like a decent person but there are subtle differences. For one thing she has put on weight and now has purple colouring in her hair.

Also I think she may have got into drugs because she is so much paler than I remember (but I can't exactly come straight out and ask her that). Most worryingly of all tho is that she has got into Yoga which is from the Buddhists and that's a slippery slope into Atheism.

I haven't witnessed her kicking a cat or sneering or being anti social or anything obvious but I was wondering if all the little changes mean she's now an Atheist or at least becoming one? If that's the case how can I reach her before it's too late?

Also she's had a dolphin tattoo on her ankle