Ahh nah man you ddidn't bother me at all, don't think that. I know how it is to be paranoid about something to work, trust me, my first post here was 'How do you select a PSU' and hell I didn't even know how you connected multiple fans haha, I was a complete noob.
But there's a lot of other knowledgable people here too and most....notice I say most and not all lol, do know what they are talking about and that card should work in your system no probs. Many people have done that.
It would be if your mobo was only AGP 2x that you'd have problems because of different voltages, but you should be good to go