זאת הטיסה הבינלאומית הראשונה שלה, ולכן היא קצת לחוצה אבל גם שמחה.

Because טיסה is a feminine noun in Hebrew.

• זה = this for a masculine noun
• זאת / זו = this for a feminine noun

Since הטיסה means the flight, and טיסה is feminine, the sentence uses זאת.

So:

• זה הספר = this is the book (masculine)
• זאת הטיסה = this is the flight (feminine)

Also, in everyday Hebrew, זאת and זו are both common.

The ה־ is the Hebrew definite article, meaning the.

• טיסה = a flight
• הטיסה = the flight

In this sentence, the speaker is referring to a specific flight: her first international flight, so Hebrew uses the definite form.

In Hebrew, adjectives usually come after the noun they describe.

So:

• טיסה בינלאומית = an international flight
• literally: flight international

This is normal Hebrew word order. English usually puts adjectives before the noun, but Hebrew usually puts them after it.

In Hebrew, when a noun is definite, its adjective usually becomes definite too.

So:

• טיסה בינלאומית = an international flight
• הטיסה הבינלאומית = the international flight

Both parts get ה־ because the whole noun phrase is definite.

This is a very important Hebrew pattern:

• ילד קטן = a small boy
• הילד הקטן = the small boy

הראשונה means the first.

It is also an adjective, and it agrees with טיסה in gender and number:

• ראשון = masculine singular
• ראשונה = feminine singular

Since טיסה is feminine singular, the sentence uses ראשונה.

So:

• הספר הראשון = the first book
• הטיסה הראשונה = the first flight

Here the phrase is: הטיסה הבינלאומית הראשונה שלה = her first international flight

Hebrew stacks descriptions after the noun.

So the structure is:

• הטיסה = the flight
• הבינלאומית = international
• הראשונה = first
• שלה = of hers / her

Hebrew often builds noun phrases this way:

noun + adjective + adjective + possessive

So although English says her first international flight, Hebrew says something more like:

the flight international the-first of-her

That sounds strange in English, but it is normal in Hebrew.

שלה means hers / of her, and in this kind of sentence it functions as her.

Hebrew often expresses possession with של + pronoun:

• שלי = my/mine
• שלך = your/yours
• שלה = her/hers
• שלהם = their/theirs

So:

• הטיסה הראשונה שלה = literally the first flight of hers
• natural English: her first flight

Hebrew usually puts this possessive form after the noun phrase, not before it.

ולכן means and therefore, so, or and that’s why.

It is made of:

• ו־ = and
• לכן = therefore / therefore so

In this sentence, it connects the two ideas:

• this is her first international flight
• therefore she is a bit nervous, but also happy

So ולכן introduces the result or consequence.

Hebrew usually includes the subject pronoun when starting a new clause like this.

So:

ולכן היא קצת לחוצה = and therefore she is a little nervous

In the present tense, Hebrew has no separate word for is in ordinary sentences, so the pronoun helps make the clause clear.

You generally would keep היא here. Without it, the sentence would sound incomplete or much less natural in this context.

In the present tense, Hebrew usually does not use a word for am / is / are.

So:

• היא לחוצה = she is stressed/nervous
• הוא שמח = he is happy
• אני עייף = I am tired

This is one of the biggest differences from English.

In past and future, Hebrew does use forms of to be more explicitly in many contexts, but in simple present-tense descriptions, it is normally omitted.

קצת means a little, a bit, or somewhat.

Here it modifies לחוצה:

• קצת לחוצה = a little nervous / a bit stressed

It softens the statement.

Examples:

• אני קצת עייף = I’m a little tired
• היא קצת עצובה = she’s a bit sad

Because they describe היא (she) and refer back to טיסה’s female traveler, so they must agree with a feminine singular subject.

Hebrew adjectives usually agree in:

• gender
• number

So:

• masculine singular: לחוץ, שמח
• feminine singular: לחוצה, שמחה

Since the subject is היא, the feminine forms are required.

It can mean either, depending on context.

The adjective לחוץ / לחוצה literally relates to pressure, so common translations include:

• stressed
• tense
• nervous

In this sentence, because it is about a first international flight, a little nervous or a little stressed would both make sense.

אבל means but, and גם means also / too.

So:

אבל גם שמחה = but also happy

The word גם shows that the second feeling is added, not replacing the first one. She is:

• קצת לחוצה = a bit nervous
• אבל גם שמחה = but also happy

So the sentence emphasizes mixed feelings.

The words that agree with the subject would change.

A masculine version would be:

זאת הטיסה הבינלאומית הראשונה שלו, ולכן הוא קצת לחוץ אבל גם שמח.

Changes:

• שלה → שלו = his
• היא → הוא = he
• לחוצה → לחוץ
• שמחה → שמח

The noun טיסה stays feminine, because the word itself is feminine regardless of who is taking the flight.

Here זאת הטיסה... is best understood as this is the flight... or more naturally in English, this is her first international flight.

Hebrew often uses זה / זאת / זו in identification sentences of the type:

• זה הבית שלי = this is my house
• זאת המורה שלנו = this is our teacher

So yes, it literally means this, but in natural translation it may simply feel like this is... rather than a strongly demonstrative this one.