Most Helpful Girl
Whatever you do, don't stop being the guy she fell for. Keep being teasing and playful AND hold her hand and tell her honestly how you feel about her. Try to get out of your head, stop worrying, and trust that this girl already KNOWS you and really likes you, and may be just as anxious as you are for everything to work out well.
Most of my dating experience has been falling for guys who were my friends first - it's the best foundation for being lovers. We just relaxed into it and enjoyed feeling ridiculously lucky that it worked out that way.
Most Helpful Guy
Isn't most of a relationship just normal everyday life? If the previous conduct was enough to incite her affections, why terminate it?
Just treat her as you normally do. That should be the main thing. The sweet thing should be an add-on.