Tengo once años
En la suposición de que alguien fingiese que esos años tuviera:
En este día tengo once años.
In Spanish, you aren't years or months old, but rather, you have and complete age - however long it is, in years, months and days. In this instance, you would say, "She is completing 11 months today." And you say it, "Ella cumple once meses hoy."
The expression to say how old you are or a material object is in Spanish is "tener ____ años".If you literally want to translate "years old" into Spanish, this would be "años de vejez", but this is nonsense to any Spanish speaker.
i am 41 years old
cien años
años de edad
You can say "Tengo cinco años".
Tienes quince años.
Tengo diezisiete anos.
Tienes deiz años.
Tiene veinticinco años.
Mis amigos tienen doce años. This is literally "My friends have 12 years", but is normally translated as "My friends are 12 years old."
In Spanish, you would say "Tengo once años." This translates directly to "I have eleven years," which is the common way to express age in Spanish.