In act 3, Why and what are the reason for Mrs. Higgins' impatience with her son and Colonel Pickering?

In chapter 3
of the playMrs. Higgins is "at-home", which means that it is a day to expect and
receive visitors

As Henry Higgins enters his mother's house uninvited, his
mother reprimands his entrance because his behavior is so rash and improper that none of her
friends what to visit when they find out that Higgins is there.

However, the
reason behind his visit is to tell his mother about the Eliza project and to tell her that Eliza
will be visiting.

Later on, after a visit from the Eynsfords and Eliza's
entrance, Mrs. Higgins begins to lose...