I'm 22 and started vaping 6 months ago while I stilled lived under my parents roof. I still had the pen and received some flack with my mother over it (Who is a smoker by the way). My father on the other hand, though not thrilled, left the choice up to me as I was an adult and supported my own hobby. After some disagreements over information about vaping, she's settled down some but her biggest standing rule to this day is if she can't smoke in the house, I couldn't vape in there either even though I've moved out since. My advice would be to sit your parents down and just tell them in a respectful manner with facts to back you up that this is a healthier alternative to smoking. I would say if your biggest worry is they won't support you in what is your choice, then don't do it around them. You can't make them change their minds if they dislike your choice and that's a fact you'll have to come to. I know I wish I could get my mother to see how much better it is, but some people are just set in their ways of thinking.