Quan era petita, vivia en un poble petit amb la meva àvia.

Because the sentence is describing a past situation as background or an ongoing state, not a single completed event.

• era = I was
• vivia = I used to live / I was living

In Catalan, the imperfect is very commonly used for:

• age or life stage in the past
• descriptions
• habits
• ongoing situations

So Quan era petita, vivia... means something like When I was little, I lived / used to live...

If you used a completed past form instead, it would sound more like a specific finished event, not a general period of childhood.

Because adjectives in Catalan usually agree in gender and number with the noun they describe.

• petita refers to the speaker, understood as a female person
• petit refers to poble, which is a masculine singular noun

So:

• era petita = I was little (female speaker)
• un poble petit = a small town/village

If the speaker were male, it would be:

• Quan era petit...

Because Catalan often drops subject pronouns when the verb ending already shows who the subject is.

Here:

• era can mean I was
• vivia can mean I lived / used to live

The subject jo is understood from context, so it is usually omitted unless you want emphasis or contrast.

For example:

• Jo vivia... would be possible, but it sounds more emphatic, like I lived...

Quan means when.

In this sentence, Quan era petita introduces the time context:

• When I was little

It is a very common way to begin a sentence that gives background in time.

Here petita means little in the sense of young or a child, not literally physically small.

So:

• Quan era petita = When I was little / when I was young

Catalan often uses petit / petita this way when talking about childhood.

Here en is used to mean in.

• en un poble = in a village / in a small town

Since the sentence describes where someone lived, en is the natural preposition.

Very roughly:

• viure en = to live in
• anar a = to go to

So:

• Vivia en un poble = I lived in a village
• Anava a un poble = I went to a village

Poble usually means village, small town, or sometimes just town depending on context.

In this sentence, because it also says petit, the idea is clearly:

• a small village or
• a small town

It is not a large city. For a city, Catalan would usually use ciutat.

Because in Catalan, adjectives often come after the noun.

So:

• un poble petit = a small village

This is different from English, where adjectives usually come before the noun:

• a small village

Catalan can sometimes place adjectives before the noun, but after the noun is the basic and most common pattern.

Catalan often uses the definite article with possessives, especially with family members.

So:

• la meva àvia = my grandmother

This is very normal Catalan.

English does not use the article here, but Catalan usually does:

• el meu pare = my father
• la meva mare = my mother
• la meva àvia = my grandmother

Because the possessive has to agree with the noun possessed.

• àvia is feminine singular
• so the possessive is meva

Compare:

• el meu avi = my grandfather
• la meva àvia = my grandmother

So meu / meva changes depending on the gender of the noun.

Amb means with.

So:

• amb la meva àvia = with my grandmother

In this sentence, it tells you who the speaker lived with.

Grammatically, you could say vaig viure, but the meaning would change.

• vivia = imperfect, giving a background situation or habitual past
• vaig viure = completed past, more like I lived for a specific period or as a finished fact

So:

• Quan era petita, vivia... sounds natural for describing childhood background
• Quan era petita, vaig viure... sounds more like you are pointing to a more definite or bounded period

For this kind of childhood description, vivia is usually the better choice.

It is very natural and helpful because Quan era petita is an introductory time clause.

So the sentence is divided like this:

• Quan era petita, = time background
• vivia en un poble petit amb la meva àvia. = main information

In writing, the comma makes the structure clearer.

Yes. That is very common.

• Quan era petita... = When I was little...
• De petita... = As a child / when I was little...

Both are natural, though Quan era petita is a bit more explicit because it includes the verb era.

Example:

• De petita, vivia en un poble petit amb la meva àvia.

Only petita would change to petit.

So it would be:

• Quan era petit, vivia en un poble petit amb la meva àvia.

The rest stays the same because:

• poble is still masculine singular, so petit stays petit
• àvia is still feminine singular, so la meva àvia stays the same

Àvia means grandmother.

The grave accent on à shows where the stress falls and also marks the vowel quality. The stress is on the first syllable:

• À-via

For learners, a simple approximation is:

• AH-vee-uh

The accent helps show that the word is not stressed later in the word.