I think it only has to be as important as you make it. If you treat it like it doesn't matter all that much, it'll have the reverse effect of being easier for you, you'll be less tense. There are really only two options, either she's not attractive at all and you can essentially just treat her like a male friend, especially since she's into gaming, or she is, in which case go into it expecting nothing and go from there. If you get your hopes up and put all kinds of expectations on yourself you'll be too judgmental of your own actions. You don't have dignity to lose, you can only gain it from this experience or nothing changes. Think of it that way. And if it helps you feel better to call upon something dark beforehand then do that too.