Personally, I think you are playing it safe, showing her the best parts of you but not generating attraction or tension. I did this many times in the past, showing how great a guy you can be then watching her go off with someone else. My coach (female) has helped me understand this alot. When you play it safe, you are generally not generating attraction.
How about trying 1 of these 2 ways: 1. I would tell her that if you continue hanging out together alone, it's under the intention of getting to know each other in the direction of a relationship. If she is not interested and only she's you as a friend, then you know what to do and it's your choice. 2. If you don't want to go that strong so soon, invite her to things you are already doing. If he says no, what does it matter, you are already doing it. Also, invite her to things you are doing as a group, but tell her she is only invited if she brings bundles of energy. This way it's less 'date' like and more about how she fits into the new life you have made over the past 4 years for you.
I would treat her like any other potential girlfriend, I learnt through my coach that we often play it more safe with the girls we are interested in than the ones we are not. The flip side is we are not staying true to ourselves and give off a different vibe.
