En junio, mi prima cumple catorce, pero su mejor amiga ya tiene dieciséis.

In Spanish, age is usually expressed with the verb tener: tiene catorce (años) = she is fourteen.

But when talking about a birthday, Spanish often uses cumplir:

• Mi prima cumple catorce = My cousin turns fourteen

So:

• tiene catorce = her current age
• cumple catorce = she reaches that age on her birthday

Spanish does not use ser for age the way English uses to be.

Both are correct. Años is often omitted when the context clearly shows you are talking about age.

So these both work:

• Mi prima cumple catorce
• Mi prima cumple catorce años

Likewise:

• Su mejor amiga ya tiene dieciséis
• Su mejor amiga ya tiene dieciséis años

Omitting años sounds natural and common.

Here, cumplir means to turn a certain age.

Examples:

• Cumplo veinte = I turn twenty
• ¿Cuántos años cumple? = How old is he/she turning?

More generally, cumplir can also mean to fulfill or to carry out:

• cumplir una promesa = to keep/fulfill a promise
• cumplir una obligación = to carry out an obligation

So the meaning depends on context.

Spanish uses tener for age, not ser.

Compare:

• English: She is sixteen
• Spanish: Ella tiene dieciséis (años)

This is one of the most important differences beginners need to remember. Using ser for age would be incorrect.

Ya often means already.

So:

• su mejor amiga tiene dieciséis = her best friend is sixteen
• su mejor amiga ya tiene dieciséis = her best friend is already sixteen

Here, ya suggests a contrast: the cousin is only just turning fourteen, but the best friend has already reached sixteen.

En junio is a time expression placed at the beginning of the sentence:

• En junio, mi prima cumple catorce...

That comma helps separate the introductory time phrase from the rest of the sentence. In English, we often do the same:

• In June, my cousin turns fourteen...

You may sometimes see less punctuation in informal writing, but the comma is very normal here.

When talking about months in a general time sense, Spanish normally uses the month name without an article after en:

• en junio
• en agosto
• en diciembre

So En junio simply means In June.

You may see articles with months in other structures, such as:

• el junio pasado in some contexts, though el mes de junio or simply en junio is more straightforward for learners.

For this sentence, En junio is the standard choice.

Spanish distinguishes male and female cousins:

• primo = male cousin
• prima = female cousin

So:

• mi prima = my female cousin
• mi primo = my male cousin

Unlike English, Spanish often makes these family words gender-specific.

Yes — su can mean several things depending on context:

• his
• her
• your (formal singular)
• sometimes their

In this sentence, context tells us su mejor amiga means her best friend, referring to mi prima.

If needed, Spanish can clarify with:

• la mejor amiga de mi prima

That removes ambiguity completely.

Because the noun refers to a female friend:

• amigo = male friend
• amiga = female friend

Since the sentence says su mejor amiga, we know the best friend is female.

Also notice the adjective agrees too:

• mejor amigo
• mejor amiga

In this case, mejor does not change form, but the noun does.

Mejor is the normal comparative/superlative form for bueno in this meaning:

• bueno = good
• mejor = better / best

So:

• mi mejor amiga = my best friend

Spanish does not usually say más buena amiga for best friend. Mejor amiga is the natural expression.

Spanish commonly writes small numbers as words in normal prose, especially in educational material:

• catorce
• dieciséis

You could also write digits:

• cumple 14
• tiene 16

But in full sentences, writing them out is often preferred, especially in textbooks and formal writing.

Dieciséis is spelled with a written accent on the final é:

• dieciséis

This is the standard spelling and you simply need to learn it as part of the word. Some numbers in this range have accents and some do not:

• dieciséis
• veintidós
• veintitrés
• veintiséis

The accent shows the correct stress pattern in the written language.

Yes, but they are usually omitted unless needed for emphasis or clarity.

Natural:

• Mi prima cumple catorce
• Su mejor amiga ya tiene dieciséis

Also possible:

• Mi prima, ella cumple catorce — but this is less neutral and usually sounds emphatic or unnecessary.
• Ella ya tiene dieciséis — useful if you want contrast or clarity.

Spanish often drops subject pronouns because the verb form already tells you the person:

• cumple
• tiene

Because Spanish often uses the present tense for facts about scheduled or expected events, especially when the time is clearly stated.

So:

• En junio, mi prima cumple catorce
  means that in June, she turns fourteen.

This is similar to English sentences like:

• In June, my cousin turns fourteen

The present tense sounds natural here because it states a known future event as part of a timeline or fact.