Help choosing a song for an audition?

I'm looking to audition for my community's theater program this year. The show requires a more "mature" sound. I know, as a 17 year old, I won't be able to have the adult-mature sound yet but I'm just looking for tips. I sing best in the high soprano range (think Pie Jesu) and high alto (any of Mother Gothel's songs from Tangled). Irritatingly, my vocal break is somewhere in the second soprano range, and so it's hard for me to sing in that range. :/ Any tips? I can also handle songs with vibrato. For previous auditions I've sung Green Finch and Linnet Bird from Sweeney Todd and even By the Sea from the same, as a few examples.