Customer order number

Hello!
I have some plugin and code like this

 public OrderExtensionRecord CreateOrderExt(Order order)
        {
            var model = _orderModelFactory.PrepareOrderDetailsModel(order);
                        
            var orderExt = new OrderExtensionRecord()
            {
                OrderId = model.CustomOrderNumber,
                Exported = false,
                CreatedDateTime = DateTime.Now
            };

            _orderExtensionRepository.Insert(orderExt);

            return orderExt;
        }

public void HandleEvent(EntityInserted<Order> eventMessage)
        {
            CreateOrderExt(eventMessage.Entity);
        }

So the problem is that on this step CustomerOrderNumber is empty. How to avoid this problem? Anny suggestion?

Solved:

OrderId = _customNumberFormatter.GenerateOrderCustomNumber(order),