Paredes wants to be in a position to pick a switch to Juve or Madrid after Russia 2018, but he is not sure which way he would lean if the situation arose.
"You know, I have many friends in Turin, but right now I have to concentrate on Zenit and then we'll see - you never know what can happen at the end of the season," Paredes told RMC Sport.
"For me, knowing there is the interest of two clubs like Juventus and Real Madrid, it is important. But I try to deal with these transfer rumours with serenity. I try not to be distracted.
"After the World Cup I will make the decision, but choosing between Juventus and Real Madrid is not easy, it would be a difficult choice for me.
"I would rather have both proposals on the table first and then choose. Meanwhile, I have to think about working and doing well otherwise I run the risk of losing the interest of these two great clubs.
"I am young and I have to think well about the choice I will make. Going to Madrid with all the champions – I'm not afraid, I would be ready for the challenge.
"But there are also many other factors that I have to evaluate and to think about before making the final decision. Family has nothing to do with it. They only want the best for me, so it's a personal choice."
Paredes revealed Juve were interested in him when he made the move to Zenit, but a deal never materialised, in part because of ardent Roma supporters.
"When Juventus were spoke of [as a suitor] the first time, the Roma fans made their voices heard and prevented the transfer," he said.
"They told me it was forbidden to move to another Italian team. At that time though my first choice was Juventus."