i would REALLY stay away from singing anything from wicked. anything.
"day by day" doesn't really fit BATB stylistically.
is this for a high school production?? if so, you might do well to try out for mrs. potts. if it's a community production i doubt they'll have someone as young as you play an "older" role.
i'm not very well versed in picking out low-range songs, since i'm a soprano..but i would recommend trying to find a ballad that seems to fit the "disney" style. i would say use "for good" as a last resort since a bunch of other girls are probably considering singing stuff from wicked.
if i come up with a more specific suggestion i'll let you know.
break a leg!
"grace, you're stuffed in a box getting rid of ass plaque. let's face it, this evening is a bust."