I'm taking dd to the cinema with a couple of friends for her birthday; should I take them to a 2D or 3D film? I've not been to one so have no idea whether they're suitable for young children; I'm wondering if you can watch them without the glasses as I can imagine fidgety 6 yos getting impatient with them over two hours; also one of her friends wears glasses, do they still work ok for glasses wearers?