Jeg er ikke træt nok til at gå i seng endnu.

Both are possible, but they mean different things.

• Jeg er ikke træt nok = I am not tired enough
• Jeg er nok ikke træt = I am probably not tired

So nok has two different uses in Danish:

1. enough

   • after an adjective: træt nok = tired enough

2. probably / presumably

   • often earlier in the sentence: jeg er nok... = I am probably...

In your sentence, nok clearly means enough, so it stays with træt.

Because in Danish, ikke usually comes before the word or phrase it negates.

Here it negates the idea of being træt nok:

• Jeg er ikke træt nok = I am not tired enough

This is very similar to English structure.

Compare:

• Jeg er træt = I am tired
• Jeg er ikke træt = I am not tired

Then nok is added to the adjective phrase:

• Jeg er ikke træt nok = I am not tired enough

Here nok means enough.

It often follows an adjective or adverb:

• varm nok = warm enough
• hurtig nok = fast enough
• gammel nok = old enough
• træt nok = tired enough

So:

• ikke træt nok til at gå i seng = not tired enough to go to bed

Be careful, because nok can also mean probably in other sentences, but not here.

Because nok til at + infinitive is a common Danish pattern.

Structure:

• adjective + nok + til at + verb

Examples:

• Han er gammel nok til at køre bil. = He is old enough to drive
• Jeg er ikke stærk nok til at løfte den. = I am not strong enough to lift it
• Hun er modig nok til at spørge. = She is brave enough to ask

So in your sentence:

• træt nok til at gå i seng = tired enough to go to bed

The at is the normal infinitive marker, like English to before a verb.

Not in this sentence.

After nok, Danish uses til at, not for at:

• træt nok til at gå i seng ✅
• træt nok for at gå i seng ❌

For at usually means in order to and expresses purpose:

• Jeg gik hjem for at sove. = I went home in order to sleep

But here the meaning is about being sufficiently tired, so Danish uses nok til at.

Gå i seng literally means go into bed or go to bed.

It refers to the action of going to bed, not necessarily sleeping yet.

So:

• gå i seng = go to bed
• sove = sleep

Your sentence is about whether the speaker feels ready to go to bed, not whether they are already sleeping:

• Jeg er ikke træt nok til at gå i seng endnu.
  = I’m not tired enough to go to bed yet.

Compare:

• Jeg vil gå i seng. = I want to go to bed.
• Jeg vil sove. = I want to sleep.

They are related, but not identical.

Here endnu means yet.

It shows that the situation may change later:

• Jeg er ikke træt nok ... endnu = I’m not tired enough ... yet

So the idea is:

• right now, I’m not tired enough
• maybe later, I will be

This is a very common use of endnu in negative sentences.

Examples:

• Jeg er ikke klar endnu. = I’m not ready yet.
• Han er ikke kommet endnu. = He hasn’t arrived yet.

Because sentence-final endnu is very natural in Danish when it means yet.

In a sentence like this, the end position sounds normal and idiomatic:

• Jeg er ikke træt nok til at gå i seng endnu.

You may also see endnu in other positions in Danish, but in simple everyday sentences meaning yet, the end is extremely common.

Compare:

• Jeg er ikke færdig endnu.
• Vi ved det ikke endnu.
• Hun er ikke hjemme endnu.

Yes, sometimes, but context matters.

Endnu can mean:

• yet in negative sentences
• sometimes still or even more / further in other contexts

In your sentence, it clearly means yet because of the negative structure:

• ikke ... endnu = not ... yet

Examples:

• Jeg er ikke sulten endnu. = I’m not hungry yet.
• Det er endnu værre. = It is even worse.

So learners should not try to translate endnu with just one English word in every context.

Because Danish uses a different construction: gå i seng.

Literally:

• gå = go
• i = in / into
• seng = bed

But the whole phrase means go to bed.

This is just an idiomatic difference between Danish and English. You should learn gå i seng as a fixed expression.

Other similar fixed Danish expressions may also use a different preposition than English.

Yes, træt is an adjective meaning tired.

In this sentence, it stays træt because it is used after er with jeg:

• Jeg er træt. = I am tired.

Danish adjectives can change in some contexts, for example:

• en træt mand = a tired man
• et træt barn = a tired child
• trætte mennesker = tired people

But after være with jeg, you use the basic form:

• jeg er træt

So here:

• Jeg er ikke træt nok...

Largely yes, which makes this sentence quite learner-friendly.

Danish:

• Jeg = I
• er = am
• ikke = not
• træt nok = tired enough
• til at gå i seng = to go to bed
• endnu = yet

So the structure is close to English:

• I am not tired enough to go to bed yet.

The main things to notice are:

• nok comes after the adjective
• Danish says gå i seng, not literally go to bed
• endnu often comes at the end

Then Danish uses V2 word order, which means the verb still stays in second position.

For example:

• I dag er jeg ikke træt nok til at gå i seng endnu.
  = Today I’m not tired enough to go to bed yet.

Notice what happened:

• I dag comes first
• er still stays in second position
• jeg moves after the verb

So not:

• I dag jeg er... ❌

but:

• I dag er jeg... ✅

This is one of the most important word-order rules in Danish.

In speech, emphasis can shift the nuance.

For example:

• Jeg er ikke træt nok til at gå i seng endnu.
  Neutral statement.

• Jeg er ikke træt nok ...
  Emphasizes that the problem is the level of tiredness.

• ... gå i seng endnu
  Emphasizes yet, suggesting maybe later.

You can also front parts of the sentence for emphasis in some contexts, but the neutral version you have is already very natural everyday Danish.

For learners, the most useful thing is to remember the sentence as a standard pattern:

• Jeg er ikke [adjective] nok til at [verb] endnu.

Examples:

• Jeg er ikke sulten nok til at spise endnu.
• Jeg er ikke klar nok til at svare endnu.