After taking a present she won't bother about bitcoins or she won't be interested in knowing that you bought with bitcoin as she has no idea what the hell bitcoin is
but if he buy it in front of her then she will try to get some bitcoins and for that he will teach her some ways of earning bitcoins and so whenever she will need to do some shopping and she will not have much money then she will try to adopt that way of earning.
That's hard to happen... If you would just buy her something using bitcoin, I doubt it if she will start asking bitcoin except if she want to take advantage of your kindness so you could use your bitcoin again to buy her another one... It's really difficult to teach someone if their interest is not in there...