Romero, 15, became the youngest player to feature in LaLiga when he came off the bench against Real Madrid last month.
The Argentina youth international has been compared to Messi, but the attacker said that made him uncomfortable.
"It bothers me because there is only one Messi," Romero told Fox Sports.
"I want to make a name for myself in football as Luka Romero."
Romero is eligible to play international football for Argentina, Mexico and Spain.
But Romero knows who he wants to represent, saying: "I can choose, but if Argentina still loves me, I will continue playing there.
"If possible, I want to play for the Argentina national team."