No doctor can tell you it will be 100% safe for you regardless of how long or how much they know about you. But I’m sure all doctors would hazard an educated guess to say there’s a good chance it will be much safer for you than smoking.
If you were to give up tomorrow and never inhale anything but clean air for the rest of your days there’s a good chance that you’ll get a cough regardless as that’s the bodies natural way of clearing your lungs. You may get a bad cough or a chest infection. No one knows as we are all different.
The main thing is that if you start to vape you are starting to get rid of all that crap you’re taking in now with the fags. You’ll be benefiting your health far more than sticking with cigarettes for fear of getting ill and eventually taking years off your life.
My advice would be to buy a little starter kit and give it a go. If you get too sick then at least you have tried. There’s always an unlucky few who don’t get on with any sort of vape in the same way as there’s always a few who don’t react well to prescribed medicine that is given to cure them.
Give it a try. You may like it and quit the smokes. You may hate it and go back to the ciggies. But if you start worrying too much about the what ifs and maybes you’ll never know and build it up to be something far worse than it most likely will be.
Gotta be worth a shot. Good luck!