For her first time, you should probably use a little wine and pot to get her really relaxed. Have some good music on the stereo, and a little lube handy. Get her off orally first to get all her senses rolling and for her to shed her inhibitions. Take it nice and slow and just gradually work it in there and it will be fine. Before long she'll be begging you for it!
Yeah, it's not something that's going to go perfectly the first time. You're going to have to do a little bit of 'work' to get to the point where you want to be.
