Guild Wars 2

As in the title, Can I do every achievements for example 3 days before the end of event or there are some achievements I need to do every day or something?

You will need to do at least 5 invasions in order to unlock the playhouse and complete the playhouse achievements before September 3rd. The invasions are sticking around permanently so you should be able to finish those achievements at any time if I had to guess.

Also be aware that one of the achievements requires 13 maps completed. Unless you plan on staying up late the last few days, I suggest doing them between now and then.