Is it normal to be nervous to make the 'first' move on my roommate?

I've lived with my current roommate for over a year now. I am now 22, she's 32. I met her when I was 15 (she was my former bosses ex wife, I met her at my old place of work). When I turned 19, we were drinking one night, and she kissed me. I had never kissed a girl before, I loved it! later that year, I had a threesome with her and her boyfriend. Then we moved in with eachother a lil over a year ago. Our first weekend in our new house, we spent downtown getting so wasted, I actually don't remember anything between when I started to puke and when I remember her having her legs wrapped around my head 5 hours later. Apparently it was great! a year later Im still super crushing on her. I love everything about her, and I know she loves me. Unless im drunk or high, I don't have the courage to say anything to her or to kiss her which ive been dying to do for a year now. I don't know why im so damn nervous, because ive kissed her and had sex with her before. Is it normal to be this nervous to just walk up to her and kiss her and tell her how I feel? Help me!