I would go ahead and buy her a real machine, for one it would be money well spent and it would last her for quite some time.
If it was me I would buy a vintage machine just for the fact that you can get them fairly cheap and they are very well made.
I have a 1974 Kenmore 1320 with all of the accessories that was only used a few times in its life and only paid $15 for it and the pecan tri-fold cabinet. I sold the cabinet and put the machine in a portable case so I could use it for classes. For a full size machine it is very light and it would be a perfect beginner machine.
Billy