Yes, passengers can easily be put off by a single bad experience, and if that passenger is somebody who is going to have a big influence on your future trips it may be a good idea to introduce them to flying trips in gentle stages.
On the one hand a flight to Paris in lovely weather, sweeping in over the gardens of Versailles and then going to stay somewhere nice might convince her straight away. On the other hand getting stuck in bad weather and spending the weekend at some little airfield in the middle of nowhere might put her off. It may well be an idea to have a few good shorter trips in the bank as it were by the time that sort of thing happens.
As rateone says, flying with passengers when you first start off does add to your stress, and on this sort of trip wih hotels booked etc. you'd be putting yourself under a lot of pressure to press on and get there - never a very good thing.