There's a point in every young actress's life when she wants to be the ingenue. She wants to be Christine Daae, Sandy, Eliza Doolittle, Cinderella, Maria von Trapp. These are all leading ladies - some are lovely damsels, wilting flowers - and they are all sopranos.
And then there's a point when the actress realizes that Reno Sweeney, Rizzo, Velma Kelly, Mame* - the altos - are actually the more fun roles to play. (Yes, of course this is a broad generalization, and yes, it does depend a lot on the play. Tracy, the "ingenue" of Hairspray is still a more "fun" role than Christine Daae.)
*You don't even really have to be a great singer for Mame. Lucille Ball, after many years of smoking, played Mame and basically spoke in rhythm for most of the songs.
When I was a teenager, I wanted so badly to play an ingenue. I wasn't the highest soprano out there, but I had a good range. The problem was, I didn't have The Look. My mom once cautioned me that a role I wanted was one the directors saw as being "pale and frail." Well, I've got the pale down. The frail... not so much.
I go more into that aspect of my time in the theatre in this post.
About the time I hit my early-mid twenties (shortly before I stopped doing theatre altogether), it occurred to me that the altos had more fun. I started auditioning for roles like Rizzo; even though I was technically a soprano or mezzosoprano, I had a decently broad range, so higher altos (like Rizzo) were perfectly feasible for me, from a vocal standpoint, at least.
Driving along in the car sometimes, belting (as best I can, now that my range is more limited) along with Anything Goes, I do kind of wish I could go back and remind myself not to ONLY audition for the leading lady. Sometimes the alto sidekick has more fun.