Is it possible somehow to share calendar with colleagues from today to the future without past? 

I describe my situation. I use my calendar since 2009 and I have there a part of my personal life as well. I did not use to mark meetings as Private. Now I would like to share my calendar but I do not want to my colleagues see my past calendar. So I have few options. I can delete all the past actions (which I do now want to), or go through past 5 years and mark everything as Private or set a new Calendar. All three options are quite bad for me.

But I cannot see possibility how to forbid sharing of past.

Any help?

create new calender, share that calender to others. Go to outlook, choose calender -> right click on calender and then add new calender. share that calender to others. hope problem solved

I think I do not understand you. I know how to create a new calendar and share it, that is not a problem. But I would like to share my current calendar but without the past.

Joby is basically saying that you can't do that. His recommendation is to create a new calendar and use that from this point on. Basically because it's probably quicker to add the future calendar items than remove 6 years of historical calendar information.