When will she offer birth?

My cat lost her plug about 3 days ago now. When will she go into graft?
Any time in a minute. While you're waiting why don't you go down to your local shelter and see if they'll let you pick out the cats or kittens that will die because your kittens will appropriate homes that would have gone to them?

Thank you for adding to the pet overpopulation problem! GET YOUR CAT and these kittens SPAYED!!
After I read this, I fell asleep HOPING that there would be some mitigating circumstances to your cat's pregnancy. The barrage of vile, seething, hate-filled comments you were subjected is, alas, disappointingly all-too-typical of the conduct of a lot of the people in this online community of (supposed-to-be) helper,

Don't hold your breath waiting for them to queue up here, and apologize for their conclusion-jumping, much less the venom in which they did so. Lashing out at race like yourself is what gives their lives (a pitiful degree, for them, anyway) of goal.

Controlling the animal overpopulation is an admirable goal. It is done a great disservice by people similar to those who berated you here, who live to tear down people who come to this forum for thoughtful advice, for the ulterior motive of somehow attitude superior to these questioners in doing so, and hence (for a fleeting second) feeling good give or take a few themselves in what must be the wretched excuses for lives that they lead, by thinking that their desperate hope that there is someone lower than them, and have that be true, in turn, negate some of their well-deserved feelings of social inferiority, personal inadequacy and damp squib. Imagine the effect that it would have had if Bob Barker, instead of his positive sign sour to The Price Is Right all those years, had ended his show echoing that shrill fascist who assaulted you next to that remark about how by not neutering your cat, that YOU are responsible for every kitten surrounded by America, no, THE WORLD, that is on death row.

It is unfortunate that their parents, apparently incompetent to raise offspring who would be capable of civil conduct as "adults." weren't themselves socially responsible adequate to have themselves spayed or neutered, so as to not contribute to the tragic problem of overpopulation of boors in society. I am certain you will raise the kittens far more responsibly than those self-loathing members of that verbal lynch mob, who sway out here to kill time between (for them) self-actualizing episodes of Jerry Springer and Maury Povich, were by their sad excuses for parents.
um...yeah. NEVER have I hear of cats "losing their plug".

just keep her close, and when the kittens are weaning, seriously consider spaying her.
It should be any time now and where on earth I understand where some people would be angry because of the population problem it's no aim for them to attack you like that I'm sorry for that. No worries the kittens should come any time now.
Answers:    These people answering are ridiculous!

Whenever our unspayed females got pregnant we just kept adjectives the babies (Yes, We have 9 cats) so I don't feel bad in the order of it and anyone who doesn't like it can stick it.

The point is that you didn't ask to be ridiculed for not spaying your cat; you want to know when she'll have the babies. I do, however, suggest good up some money and spaying her as soon as you can.

Unfortunately it's really random. Labor could start anytime in the next 24 hours. She'll quality more comfortable if you don't follow her around. Love on her if she's around but don't bug her if she's hiding sour.
Shouldn't YOU know, if you enjoy an unspayed female who you allow to get pregnant? Shouldn't you at least be responsible contained by doing the research well beforehand?
How is sexing done surrounded by cats?   Moving intertwine within Kitties Stomach?   Uh oh my kitten's bark approaching a puppy?   My Cat is really a boy! can any one comfort me beside some correct name?