This could go one of 3 ways... I'll get the worst out of the way first...
1 - No matter what you say or do she won't be interested.... Would be a sad end point, but it can clearly happen.
2 - Get her something like the Smokeless Image Volt, Halo G6, or Bloog - These "look" much more "ordinary" and are much less likely to "stand out" if she's concerned about that.
3 - Get her interested in something more substantial, at minimum an eGo type.
There are really too many unknowns here to really be of too much help to you... How much does she smoke? This will be a big determining factor as to whether a 808D like the Halo G6 etc will fit the bill...
"Why" does she smoke? Enjoyment? May be more willing to go for the eGo style. Socially? Maybe the G6 is more suitable, etc...
Does she like the tobacco flavor, or would she be interested in better, true, flavors...
Maybe equate it to a Hooka to some degree, which are growing more familiar with younger crowds lately and people seek for the social aspect and flavors are MUCH more common in that world.
Bottom line is I really think the conversation needs to be about introducing her to a safer world she may not be familiar with, and dispelling the many myths.. Maybe a friend had a bad experience with a mall or gas station ecig, etc...
Education is everything, I think any new potential vaper needs to understand what's available out there from the hardware to liquids, etc.. Prefilled carts are all some are interested in, where some (myself included) spent countless time and money trying MANY different devices and ending on a ProVari....
The other question for her, you, and her mother - does she want something to help quit, or does she enjoy it / is looking for a long term alternative...
Sorry for the rant, but I hope this may help...