[quote=RainDash]
I just have a problem with a fifteen year old just being able to initiate HDWM on her own, but maybe I missed something in her past that made her able to just enter it.
[/quote]

Though she is older than Tsuna...? She was trained longer than Tsuna too. 
In fact, age is hardly revelant at all.

Plus 7 years is longer than one year. A lot longer.

Also consider what universe this is. Children are sucessors of various mafia families. 
Your argument is disregarding the entire nature of Katekyo. Not only that, my character isn't in charge of all the Yakuza. Just a family of the Yakuza. Yakuza has an infrastructure all its own. Though, either way, the character was born into it and was appointed her rank through her mother and, eventually, via her own great strength. 

You are being very narrow. Like, looking at the scenario far too realistically. Not only that, flames are hardly strictly a Vongola art. Once shown how, flames can be utilized by many different sorts of people from many different walks of life.