I was invited, however I am only 16. If I demonstrate my skills and my technical ability, is it likely that I will be able to proceed or will I be axed the first group? Any further advice is appreciated.
I can't tell you what Apple's hiring practices are but if you can get into such an event, you should do it. If anything, it tells you what is involved and you in turn, can measure your own ability against the demands that will be put for before those attending. In short, you get at worse, a preview if you are not of hiring age. (Consider it like auditing a class before actually taking the class.)