You can currently only book up to 12 August. That is 88 days from today, so I agree that you would think it possible to book today for 14 August. However it looks as though you will have to wait 2 more days, but remember everyone is in the same boat so you will still have the same chance of getting your confirmed booking.
The 30 berth allocation is simply the general allocation, you must remember that berths will also be held for the Road Side quota, the Remote Location quota, the Pooled Quota, Tatkal etc. etc.