Is it okay to sell the only house without vacating it?

You can't. If the house is sold, it will not vacate. For housing transactions, after the money and goods are close, the seller collects the purchase price and assists in the transfer of real estate rights, and the property rights belong to the buyer. However, considering that it will take some time for the seller to move, generally, the buyer and the seller will reach a certain signing agreement and give the seller a few months' transitional period to move out. Therefore, it is impossible for it not to vacate, which is based on the particularity of commercial housing transactions, but don't think that it can't move out for a long time after selling the house, and the buyer can only sue for breach of contract after the transfer of real estate rights.