Need Interview Help...

Ok I work on a busy med/surg floor. We are doing primary nursing and have gotten rid of "charge nurses". Our manager posted an available job opening for a care cordinator/resource nurse. The roles are similar as far as leading, making assignments, checking charts, being a go to for Docs. So long story short. I didn't apply the first time around and only one offer was made (2 openings) Then they opened the position up again and I applied. I am sure during the interview they will ask why I choose to put an application in the 2nd time around and not the first.

Here is my reasoning, please help me figure out how to word it for an interview (of course not too look bad, I need a positive spin)

I wasn't sure that I was ready to jump into a leadership role as there are many other nurses on the floor that have more experince than I. Although along with that experience comes their laziness and attitude. I am a younger nurse with only 3 years behind me but I am kind, compassionate and I really do love nursing. I decided to apply because I can't help the negativity on the floor if I don't offer to step up and be a leader/example
I guess in short, I was scared to apply even though others were telling me I should. I also wasn't sure if the new stress load was worth it even though I seem to naturally fall into the leadership role. How can I make this sound good, I need to focus on strengths not that I was scared lol