don't tell me that you're affraid of what you friends might think. If you both are among friends, there should be no pressure why don't you simple ask her out. It's easy, simple and you get a straight answer. If she agree you can talk with her later more privately but if she refuse the invitation there's no problem you can still the conversation in group. Get a seat next to her or near her and ask her. A simple approach usually gets good results. Good Luck