Ben telaşlı olunca hata yapıyorum, bu yüzden önce derin nefes alıyorum.

Yes, Turkish often drops subject pronouns because the verb ending already shows the person.

• yapıyorum = I am doing / I do
• alıyorum = I am taking / I take

So Ben is not strictly necessary here. The sentence could simply be:

Telaşlı olunca hata yapıyorum, bu yüzden önce derin nefes alıyorum.

Adding Ben gives a little extra emphasis, something like:

• As for me...
• I, personally...

It can sound natural if the speaker is contrasting themselves with someone else or emphasizing their own habit.

Telaşlı is an adjective meaning flustered, rushed, anxious, or in a panic/hurry, depending on context.

So:

• telaşlı = in an agitated or hurried state

In this sentence, it describes the speaker’s condition before they make mistakes.

A very literal breakdown would be:

• telaş = rush, panic, agitation
• -lı = having, with

So telaşlı is roughly in a state of rush/panic.

Olunca comes from the verb olmak (to be / to become / to happen) plus the ending -ınca / -ince / -unca / -ünce.

Here:

• ol- = be / become
• -unca = when / once / whenever

So telaşlı olunca means:

• when I get flustered
• when I’m flustered
• whenever I become rushed/panicky

This ending often gives a time or condition meaning:

• Eve gelince beni ara. = Call me when you get home.
• Yorgun olunca çabuk sinirleniyor. = When he gets tired, he gets irritated quickly.

In your sentence, it expresses a repeated situation: when(ever) I get flustered, I make mistakes.

Both can work, but they are slightly different in feel.

• telaşlı olunca = when I am/become flustered
• telaşlanınca = when I get flustered / when I start panicking

The first uses an adjective plus olmak, which focuses on being in that state. The second uses a verb, which focuses more on entering that state.

So:

• telaşlı olunca sounds a bit more descriptive/state-based
• telaşlanınca sounds a bit more action-based/dynamic

In everyday Turkish, both are natural.

In Turkish, hata yapmak is the standard expression for to make a mistake.

• hata = mistake
• yapmak = to do / to make

So literally it is to do/make a mistake, just like English make a mistake.

Examples:

• Hata yaptım. = I made a mistake.
• Çok hata yapıyor. = He/She makes a lot of mistakes.

This is a very common noun + yapmak structure in Turkish.

Yes, -yor is the present continuous form, but in Turkish it is also often used for habitual actions, not just actions happening right now.

So:

• hata yapıyorum can mean I am making mistakes or I make mistakes
• nefes alıyorum can mean I am taking a breath or I take a breath

In this sentence, the meaning is habitual/general:

• When I get flustered, I make mistakes, so I first take a deep breath.

So although the form is technically present continuous, the natural English translation is often simple present.

Bu yüzden means because of this, for this reason, or simply so / therefore.

Breakdown:

• bu = this
• yüzden = because of, due to, for the reason of

Together:

• bu yüzden = therefore / so / because of this

It connects the first part of the sentence to the result:

• I make mistakes when I get flustered, so...
• Because of that, I first take a deep breath.

Other common connectors with a similar role are:

• bu nedenle = for this reason
• o yüzden = that’s why / so

Önce means first or beforehand.

In this sentence, it tells you what the speaker does as an initial step:

• bu yüzden önce derin nefes alıyorum
• so I first take a deep breath

Turkish word order is flexible, but placement affects emphasis. Here, putting önce before the action makes the sequence very clear.

You could also hear:

• Bu yüzden derin nefes alıyorum önce.

But the original order is more neutral and natural in many contexts.

Yes. Derin nefes almak is the normal Turkish expression for to take a deep breath.

Breakdown:

• derin = deep
• nefes = breath
• almak = to take / to receive

So it matches English very closely.

Examples:

• Bir derin nefes al. = Take a deep breath.
• Sakinleşmek için derin nefes alıyorum. = I take a deep breath to calm down.

The standard verb is almak (to take), just like English.

• nefes almak = to breathe / to take a breath

There is also:

• nefes vermek = to exhale / breathe out
• nefes almak ve vermek = to inhale and exhale

So in your sentence, derin nefes alıyorum means either:

• I take a deep breath
• I breathe deeply once

But the most natural translation here is I take a deep breath.

Yes, -ınca / -ince / -unca / -ünce can be translated in different ways depending on context:

• when
• whenever
• once
• sometimes something close to if, though less directly

In this sentence, the best reading is when(ever):

• Ben telaşlı olunca hata yapıyorum
• When/Whenever I get flustered, I make mistakes

Because the main verb is also in a general/habitual form, the whole sentence sounds like a repeated personal tendency, not a one-time event.

Yes, definitely. In fact, that is probably the best interpretation.

The sentence expresses a pattern:

• When I get flustered, I make mistakes, so I first take a deep breath.

It is not mainly about what the speaker is doing at this exact moment. It describes what they typically do in that situation.

That is very common in Turkish with -yor forms.

The comma is helpful, but Turkish punctuation is often a bit more flexible than English punctuation in casual writing.

Here the comma separates:

1. the reason/background: Ben telaşlı olunca hata yapıyorum
2. the result: bu yüzden önce derin nefes alıyorum

So the comma makes the sentence easier to read. It is natural and appropriate.

Yes, Turkish allows several word orders, though emphasis changes.

Original:

• Ben telaşlı olunca hata yapıyorum, bu yüzden önce derin nefes alıyorum.

Possible alternatives:

• Telaşlı olunca ben hata yapıyorum, bu yüzden önce derin nefes alıyorum.
• Bu yüzden önce derin nefes alıyorum; ben telaşlı olunca hata yapıyorum.
• Ben telaşlı olunca, bu yüzden önce derin nefes alıyorum would be less natural because bu yüzden needs a clear previous statement/result relationship.

The original version is very natural because it presents:

1. the problem,
2. then the response.

The sentence has two main parts:

1. Ben telaşlı olunca hata yapıyorum

   • Ben = I
   • telaşlı olunca = when I get/am flustered
   • hata yapıyorum = I make mistakes

2. bu yüzden önce derin nefes alıyorum

   • bu yüzden = so / for this reason
   • önce = first
   • derin nefes alıyorum = I take a deep breath

So the whole logic is:

• condition/situation → problem → solution/response

That makes it a very useful everyday sentence pattern in Turkish.