Learn Hardcore Portuguese (Portugal): Hoje estou nervoso e preciso de me acalmar antes do exame. - Today I am nervous and I need to calm down before the exam.

Portuguese, like English, distinguishes between a temporary state and a more permanent characteristic, but it does this using two different verbs: estar and ser.

Estou nervoso ≈ I am nervous (right now / today) – a temporary state.
Sou nervoso ≈ I am a nervous person (by nature) – a more permanent trait in your personality.

In this sentence, you are talking about how you feel today, before the exam, so it’s a temporary state → estou nervoso is the natural choice.

Does nervoso change if the speaker is female?

Yes. Adjectives in Portuguese agree with the gender and number of the person or thing they describe.

Male speaker (singular): estou nervoso
Female speaker (singular): estou nervosa
Group of males / mixed group: estamos nervosos
Group of females: estamos nervosas

So a woman would say:
Hoje estou nervosa e preciso de me acalmar antes do exame.

Why is there no eu at the beginning? Could I say Eu hoje estou nervoso?

Portuguese is a “null subject” language, which means the subject pronoun (like eu, tu, ele, etc.) is often dropped, because the verb ending already shows who the subject is.

Estou nervoso already clearly means I am nervous, because estou is the first-person singular form of estar.

You can say Eu hoje estou nervoso, but in European Portuguese that often sounds like you’re:

Contrasting yourself with someone else, or
Putting extra emphasis on eu (“Me, today, I’m nervous…”).

The most natural neutral sentence is simply:
Hoje estou nervoso…

Why do we say preciso de and not just preciso?

In European Portuguese, the verb precisar (to need) normally takes the preposition de when followed by a verb or a noun:

With a verb: preciso de estudar – I need to study
With a noun: preciso de ajuda – I need help

So here:

preciso de me acalmar = I need to calm down

In Brazilian Portuguese, people usually drop the de before a verb:

Preciso estudar / preciso me acalmar (Brazil)
Preciso de estudar / preciso de me acalmar (Portugal)

Since you’re learning Portuguese from Portugal, preciso de is the normal, standard choice.

What is the function of me in preciso de me acalmar? Why can’t I just say preciso de acalmar?

Acalmar-se is a reflexive verb when you mean to calm oneself down.

acalmar (non-reflexive) = to calm someone/something
- Quero acalmar a criança. – I want to calm the child down.
acalmar-se (reflexive) = to calm oneself down
- Quero acalmar-me. – I want to calm down (myself).

In preciso de me acalmar:

me = myself
acalmar = calm

Literally: I need to calm myself (down).

If you say only preciso de acalmar, it sounds like you’re leaving out the object:

“I need to calm… (who? what?)”

So to say calm down about yourself, you must include the reflexive pronoun: me.

Can I also say preciso de acalmar-me instead of preciso de me acalmar?

Yes, both are used in European Portuguese:

preciso de me acalmar
preciso de acalmar-me

They mean exactly the same thing: I need to calm down.

Notes on style/usage:

In everyday speech in Portugal, preciso de me acalmar is very common and natural.
In more formal or traditional grammar, you will often see preciso de acalmar-me, with the pronoun attached to the end of the infinitive (acalmar).

If you’re aiming for European Portuguese:

For speaking: preciso de me acalmar is perfectly fine.
For careful/formal writing: many teachers still prefer preciso de acalmar-me.

Why is it antes do exame and not antes de exame?

There are two points here: the preposition and the article.

The preposition
After antes, you must use de:
- antes de = before
The article
When antes de is followed by a specific noun, Portuguese normally uses a definite article (o, a, os, as):
- antes do exame = before the exam
- antes da reunião = before the meeting

So:

de + o (the) = do
antes de o exame contracts to antes do exame

Antes de exame (without the article) is not how a native would say it in this context. You’re referring to a particular exam you know about, so you use o exame → do exame.

What exactly is do in antes do exame?

Do is a contraction of the preposition de and the definite article o:

de (of, from, before in this structure)
o (the, masculine singular)
= do

Since exame is a masculine singular noun (o exame), you get:

antes de o exame → contracted to → antes do exame

Could I also say antes do exame começar? Is there any difference?

Yes, you can say:

antes do exame – before the exam
antes do exame começar – before the exam starts/begins

The meaning is very close. The second one is just more explicit about the action of the exam beginning. In everyday conversation, antes do exame is usually enough, because the start of the exam is understood from context.

Can I move hoje to a different position, like Estou nervoso hoje?

Yes. Hoje (today) is quite flexible in terms of word order. All of these are possible:

Hoje estou nervoso… (very common, slightly emphasizing “today”)
Estou nervoso hoje… (also natural)
Hoje, estou nervoso… (with a comma you add a tiny pause/emphasis)

In practice, Hoje estou nervoso and Estou nervoso hoje mean the same thing. In Portuguese (especially in Portugal), Hoje estou nervoso is very common.

Could I use relaxar instead of acalmar, like preciso de relaxar?

You can, but there is a nuance:

acalmar-se = to calm down (reduce agitation, anxiety, or emotional intensity)
relaxar = to relax (loosen up, rest, be comfortable; can be physical or mental)

In the context of being nervous before an exam, a native speaker in Portugal will very naturally say:

preciso de me acalmar – I need to calm down (emotionally)

Preciso de relaxar is also grammatically correct and understandable, but it suggests a bit more of general relaxation (rest, leisure) than specifically reducing exam nerves. Both are possible, but acalmar(-se) is the more precise verb here.

Is this sentence specifically European Portuguese? How would a Brazilian Portuguese speaker likely say it?

The sentence is in European Portuguese mainly because of:

preciso de me acalmar (with de)

A Brazilian Portuguese speaker would more likely say:

Hoje eu estou nervoso e preciso me acalmar antes da prova.

Main differences:

Brazilians often keep the subject pronoun: eu estou.
They normally drop the “de”: preciso me acalmar (not preciso de).
For “exam”, Brazilians very often say a prova (feminine), so: antes da prova. In Portugal, o exame is more common in this context.