My wife and I have our 8 year grand daughter living with us. Her mom smoked as well and when she came to stay with us and I was still smoking (outside) and came in would comment on how nasty I smelled and how bad cigarette smoke smelled. When I first got my Ecig she was pretty intrigued with the light at the end and couldn't figure out how it could produce what looked like smoke but smelled good. Like you I explained that they were for adults only and I was using in place of cigarettes to help kick the habit. She showed interest the couple of days and after that has shown no interest at all in me vaping, other than the other day when she came around while I was vaping a new fruity flavor. Our other 8 grand kids have been over and seen me vape and have shown no interest at all other than ask what I was doing and expressed same interest as our grand daughter. When I explained, their reaction was almost identical to our grand daughter. None have ever asked to try it, picked one up or asked any further questions.
I think with most kids if you are open about what the Ecig is, why you are vaping, and explain why they shouldn't touch, they will be interested for a little while but will soon put it out of their minds. I agree that the liquids should be kept up and away for safety.