Эта футболка мягкая, но её рукав слишком длинный для меня.

In Russian, the verb to be is usually omitted in the present tense.

So:

• Эта футболка мягкая = This T-shirt is soft
• literally: This T-shirt soft

The same thing happens in the second part:

• её рукав слишком длинный = its sleeve is too long

Russian normally does not use a present-tense equivalent of is/am/are in everyday sentences like this.

Because they agree with футболка, which is a feminine singular noun.

• футболка = feminine
• эта = this (feminine singular)
• мягкая = soft (feminine singular form)

Russian adjectives and words like this/that must match the noun in:

• gender
• number
• case

So:

• masculine: этот мягкий свитер
• feminine: эта мягкая футболка
• neuter: это мягкое платье

That is why both words take feminine endings here.

It can mean both, depending on context.

In this sentence, её refers to футболка, which is a feminine noun. So её рукав means its sleeve or more literally her sleeve, but in English we normally say its for objects.

Important point: Russian uses the same word её for:

• her
• its (when the noun being referred to is feminine)

So here:

• футболка is feminine
• therefore её рукав = its sleeve

Russian does not always separate her and its the way English does.

Yes, absolutely.

Both are possible:

• её рукав слишком длинный для меня
• у этой футболки рукав слишком длинный для меня

The second version is often a little clearer because it repeats the noun instead of using a pronoun.

Roughly:

• её рукав = its sleeve
• у этой футболки рукав = this T-shirt has a sleeve that is... / the sleeve of this T-shirt...

Russian often allows both styles. Using её is natural when the reference is already clear.

Because рукав is a masculine noun.

In Russian, the adjective must agree with the noun it describes:

• рукав = masculine singular
• so the adjective must also be masculine singular: длинный

Compare:

• длинный рукав = a long sleeve
• длинная футболка = a long T-shirt
• длинное платье = a long dress

So even though футболка is feminine, длинный matches рукав, not футболка.

Russian can use the singular here if the speaker is talking about the sleeve length in a general way, or about one sleeve as representative.

So её рукав слишком длинный is understandable and grammatical.

But in real life, many speakers might also say:

• у этой футболки рукава слишком длинные для меня = the sleeves of this T-shirt are too long for me

That version may sound more natural if you mean both sleeves.

So:

• singular рукав = acceptable, especially if focusing on the sleeve as a feature
• plural рукава = often natural if both sleeves are too long

Because the preposition для requires the genitive case.

The base pronoun is:

• я = I

But after для, it changes to:

• меня = me / for me

So:

• для меня = for me

This is a very common pattern:

• для меня = for me
• для тебя = for you
• для него = for him
• для неё = for her
• для нас = for us

Слишком means too in the sense of more than necessary or excessively.

So:

• слишком длинный = too long
• слишком дорогой = too expensive
• слишком холодно = too cold

It is not the same as English too meaning also.
For also, Russian uses words like тоже or также.

So in this sentence:

• слишком длинный для меня = too long for me

Yes, Russian word order is flexible, but this version is neutral and natural.

Basic structure here:

• Эта футболка мягкая = topic + description
• но = but
• её рукав слишком длинный для меня = second statement

You could change the order for emphasis, for example:

• Но её рукав для меня слишком длинный
• Для меня её рукав слишком длинный

These alternatives shift emphasis slightly:

• для меня earlier = stronger focus on for me
• слишком длинный later = builds toward the main complaint

But the original sentence is a straightforward, neutral way to say it.

In most ordinary Russian writing, ё is often written as е, so you may see:

• её
• ее

Both mean the same thing here.

However:

• её is the more precise spelling
• for learners, using ё is helpful because it shows the correct pronunciation and avoids confusion

So if you are studying Russian, it is a good idea to remember this word as её.

This sentence is correct and understandable, but native speakers might also say things like:

• Эта футболка мягкая, но рукава мне слишком длинные.
• Эта футболка мягкая, но у неё слишком длинные рукава.
• Эта футболка мягкая, но мне рукава длинноваты.

These alternatives can sound a bit more natural if you mean both sleeves.

A few notes:

• рукава = sleeves
• мне слишком длинные = too long for me
• длинноваты = a bit too long / somewhat on the long side

So the original sentence is good Russian, but there are several natural variants depending on exactly what you want to emphasize.