it's my 'D day for me.

Today is my 'D day, But how can I describe perfectly about it.
Anyway, because I think that I can't use my English to describe such a serious situation quite well. Sometime, I wish I could use computer program to show or to describe sth to the people what my feeling is.
Back to my sroty, Actually, we, the Oyama college students, had a great meeting to have a chance to listen a architecral industry company manager's talk. It made me feel like " Oh yeah I see it's a real work we have to do in the future. Can u guess what is it?
I'll give the answer next week. Feel free to answer. An also thank you for any possible reasons you can mention to prove your answer.
From TOTO