What should I do? I only notice now that I had one message unread...of a biggest multinational company, asking for a interview in early November.

What should I do? Last year, I’ve sent some CVs to various companies in order to get a new job abroad… However I started to work in my country last summer and i’ve changed my student e-mail to a professional one. Recently (yesterday) I went to check my previous e-mail box, and I had only one message unread…of a biggest multinational company, asking for a interview in early November. Now…I Know that an oppurtunity like this might only knock on my door one time, and I really wanted to just….try! But I’m too afraid to answer it or even try to explain it… Cause it may possible turn out into a situation where I give them all the reasons to never notice me again…And it’s really possible that they’ve already filled the position…. So… what would you do?