State: TN

As a teenager, I attempted to start a trash can fire as a prank which resulted in a house fire 5 years ago and was found guilty of arson once I had turned 18.
I periodically receive a letter from a lawyer's office that states:

"A judgment has been entered by the court against you which entitles Morgan & Pottinger (attorneys) to proceed with remedies through the court to collect this obligation on behalf of State Farm."

And then they ask me to pay them $118,000 and they mention payment plans are an option.
Now the $118k is not court ordered restitution. I was ordered to pay $7500 by the courts. I paid it and completed 4 years probation.

I want to buy a house but am afraid they could seize my equity after I make the down payment or in the future. Could this happen? They haven't turned it over to any collection agency though and it does not appear on my credit report. And it was in 2005!
Thanks.