Well honestly I wouldn’t worry too much. At this point defining roles might put more of a strain on things than just winging it. Forget about roles for a bit and both of you talk, and share ideas, and come up with some rules. That’s the fun bit!
They could be rules for both of you, or rules you set each other. Things like how often you have to edge, trying it in different places, different ways. Make sure you build in some shared edges too.
Talk about these ideas, write them down as you do, and make the whole process sexy. Start touching each other as you talk. Edging the other person, opening up their mind to new ideas or fantasies they hadn’t shared yet.
Also go through my tasks and denial buddies tags, there’s loads of hot ideas in there.
So make the planning something you do together, at least at first. And THEN, as you explore, you can see if you enjoy naturally taking more of a lead. Let it happen organically rather than just forcing it. Make up some games where you take the lead, see how the two of you like that dynamic, and learn as you go.
Try a bit of bondage, tying her up will bring out the dom in you. But besides agreeing safewords, really, as long as you keep talking, and go slow, you can’t easily go wrong.