Let’s see if I can think of anything that could work. What about:
[name]Lia[/name]
[name]Lilia[/name]
[name]Lily[/name]
[name]Rilee[/name]
[name]Aura[/name]
[name]Mari[/name]
[name]Malia[/name]
[name]Ria[/name]
[name]Mai[/name]
[name]Maia[/name]
[name]Lee[/name]
I like [name]Mia[/name] too - it’s spunky, but I think it works for a serious/quiet type.
You have some great options! A few more:
[name]Mila[/name]
Auri
[name]Millie[/name]
[name]Rillie[/name] (could spell it Rili)
I like [name]Mia[/name], [name]Millie[/name], [name]Aura[/name]/Auri, and [name]Mai[/name] the best for you.
Maurilia
Some “adult” suggestions might be repeat but these are what I like…
[name]Aura[/name]
[name]Ilia[/name]
[name]Maura[/name]
[name]Malia[/name] (I can see this working since you are older than [name]Malia[/name] [name]Obama[/name], I think friends at College might make a remark about it at first esp right now the the elections but would get over it quickly. However, I can see people shortening [name]Malia[/name] to [name]Lia[/name] sooner or later).
I really like [name]Mia[/name], [name]Lily[/name], or even [name]Millie[/name] for you. 
They are sort of cute, but I think they age well. My first thought was [name]Mari[/name], but I know a [name]Mari[/name] (who pronounces her name like [name]Mary[/name], not MAH-ree), and she’s sort of ridiculous, lol, so I am not so much a fan of the name anymore. I do think [name]Mari[/name] is adorable, though. I especially like [name]Lily[/name]/[name]Lilia[/name]–while you’re still fairly young, you can still be [name]Lily[/name], but you can go to the more mature [name]Lilia[/name] whenever you want.
I think [name]Lia[/name]/[name]Lila[/name]/[name]Lela[/name] (or however you want to spell [name]LEE[/name]-lah) would be great options, too…
Good luck!
I’ve always loved the nn [name]Rilla[/name] (from the [name]Anne[/name] of [name]Green[/name] Gables series). [name]Mara[/name] seems like a very sensible, mature choice to me.