Hmm... could you talk to her about it, so you know how she feels, and use that to decide what to do in the future? Like... ask her what she'd do if you just greeted her with a hug one day, instead of asking her first, if she'd be ok with it? That way you can maybe get an idea of whether she'd welcome it, and if so, you can spontaneously hug her in the future to your heart's content, without having to worry as much?

Or am I missing the point (sorry if so!)