I am, at this current point in time, 22 years old. I am also female.
Some Fanfictions from non-FF.net sites I recommend you take a look at
The Smallest Slytherin Trilogy by Rebecca Webb
Book 1 - The Smallest Slytherin
Book 2 - An Obedient House
Book 3 - Salazar's Orphans
The above is one the best writen, and well thought out stories I have ever come across.
It has the feel of a real novel, is the length of a real novel, and the author has parodied a few well known muggle songs.
Our House by Madness being one of them.
A quick taste of above mentioned song:
Sorting hat gives us the best
Salazar inspires us and Malfoy keeps the thugs in line.
Baron guards us in our sleep
Snape has got a date to keep, he can't hang around.
In our chilly dungeon deep
And the scenario in which it features, is sure to crack you up.