how long will take to close in new development

i was about to sign the contract in a new development boutique condo building. the actual unit is move in ready, and the building is almost finished except the lobby and minor work on the hall way on the higher floors. I have been told by the sponsor's broker the building has already signed off, waiting for the TCO. they are Targeting the 1st closing in 2 months. after my attorney reviewed the contract and advise me that the offer plan is not been declared yet. my deal will make the last one qualify the percentage to file for declare effective. the sponsor broker told me they are confident to do the 1st closing with in 90 days. Does anyone know usually how long will take to close on this apartment in this case.