[quote=@role model]
Natasha was trained by the KGB at a very young age, less than 10. She was inducted into a "Red Room" program for young girls who would be trained killers. And yeah, I don't like superpowered characters. Some people can pull it off, while others not. There's usually a mix when it comes to superpowered people.
[/quote]

One thing to keep in mind, from Wiki: In 1991, after the dissolution of the Soviet Union, the KGB split into the Federal Security Service and the Foreign Intelligence Service of the Russian Federation. After breaking away from Georgia in the early 1990s with Russian help, the self-proclaimed Republic of South Ossetia established its own KGB (keeping this unreformed name). In addition, the Republic of Belarus has also established its own national security agency, the State Security Committee of the Republic of Belarus, the name and acronym of which are identical to those of the former Soviet KGB. 

Which incarnation of the KGB were you intending to have her trained if you decide to go with that? I would also consider the ideas [@Raistlin Majere] mentioned.