Just as Isaac said. The only firearms that are registered in this state are NFA firearms; even then, these firearms are registered with the federal government, and not the state of Ky.
Most newbies believe when you buy a new firearm from an FFL that they are registering the firearm with the paperwork (form 4473) that you fill out at the time of sale, and that they call in. This is not true. The paperwork is used to call in a background check on the buyer, and then it sets in the dealers possession for the next 20 years, or until they go out of business. The firearm is not "registered" to your aunt unless it is a pre-'86 full automatic, a short barreled rifle or shotgun, a suppressor (aka silencer), or an AOW such as a smooth bore shotgun with a barrel under 18". Being as it is just a regular handgun, tell her to hand it to you and that is it. Check out KRS 237.020 and 527.100.
Edit: I neary forgot, she can only sale the handgun to you as long as both of you are a resident of the same state. I see you are from Ky, so as long as she is also from Ky, then you are good to go. If she is from another state then it is a violation of federal law to conduct a private transfer.