So, she draws and plays guitar. But that doesn’t mean she's half the woman you are. There are obviously some qualities you have that made your boyfriend fall in love with you, otherwise there wouldn't be any discussion of marriage.
Instead of comparing yourself to this other girl, and automatically labeling her as competition, try to befriend her. Getting close to her may keep any imagined female rivalries at bay. If your boyfriend seems ‘smitten,’ (real or imagined) it will be difficult to get around both you and this girl’s boyfriend, particularly if the two guys are best buddies.
Try not to imagine what isn’t there. If there is some unspoken attraction between these two, than you’ll know it soon enough. Meanwhile, remain confident and friendly and pay
extra special attention to your boyfriend when you get home.
Remember, there’s one thing you’ve got that she doesn’t….
HIM!