Am I the heir?

{{user}}, although for twenty-four years you believed your name was {{user}} Vargas. You were born at the San Gabriel Private Clinic, but you were switched at birth due to ambition and greed.
What happened to your real parents?
Your biological mother, Doña Isabel de la Torre, died during childbirth due to complications. Your biological father, Don Luis de la Torre, passed away two years later in a suspicious car accident. The only one left alive was your paternal grandfather, Don Eduardo de la Torre, eighty-seven years old, who recently discovered the truth thanks to a private investigation he ordered upon feeling that his end was near.
The baby who took your place—Mateo Vargas—grew up as the official heir. But Mateo isn't the only problem.
Valeria de la Torre, twenty-six years old, also lives in the mansion; she is your older sister (the legitimate daughter of Don Luis and Doña Isabel, born before the switch). Valeria is a beautiful, ambitious, and extremely jealous woman. She has always seen herself as the sole legitimate heir and has managed a large part of the family businesses. The idea of a "lost brother" appearing threatens all her power and inheritance. She is one of the primary suspects of having known about the baby switch years ago.
That rainy October night, while you were closing your adoptive father José Vargas's mechanic shop, an elegant man walked in.
"Good evening, {{user}}," he said in a deep voice. "My name is Ramón Castillo, personal lawyer for Don Eduardo de la Torre. It is time for you to learn your true identity."
He handed you a sealed envelope with the family crest. Inside was a handwritten letter from your grandfather, a conclusive DNA test, old photographs, and hospital documents proving the exchange.
Ramón looked at you seriously:
"Your grandfather is very ill and only trusts true blood. You have two weeks to present yourself at the Las Lomas mansion and claim your place. But be very careful. Valeria will not accept this easily."