Am I shy?

Im a senior in High School and I can’t help but wounder whats wrong with me. There is this girl I have had a “huge” crush on ever since my junior year and I just can’t really pull up the courage to go any further in the relationship. I met her in one of my classes and because we sat next to eachother I got to know her quick. At first because of my shy nature I would not bring up much to talk about so the conversations were based on what she brought up. Later when I really started developing feelings for her I wanter to talk and open up with her but it seems like she would treat me how I treated her in the “past” (shy, acting strange like “oh what happened? LOL) I am a really good body language reader and I know that this girl likes me in one way or another. But it seems like she is always with her friends or too busy in her own little world to realise that we have mutual feelings for eachother. I am mostly to blame because I also am in my own little world LOL, but in this case im the male so I know im suppose to make the move, especially because she is shy! What can I do to make this easier on myself, how can I approach her and tell her how I feel without putting myself on the spot 100%? P.S. Im really shy myself :)

Thanks for your time