אני תמיד מתבלבלת בין שתי הכתובות האלה.

Because the speaker is female.

In Hebrew present tense, the verb agrees with the subject in gender and number.
So:

• אני תמיד מתבלבלת = a woman saying I always get confused / mix them up
• אני תמיד מתבלבל = a man saying the same thing

A common thing for English speakers to notice is that אני itself does not show gender. The gender shows up in the verb form.

Yes. אני is used by everyone.

Hebrew does not have separate words for I depending on gender. Instead, gender often shows up elsewhere in the sentence, such as:

• the present-tense verb: מתבלבלת / מתבלבל
• adjectives: עייפה / עייף
• sometimes past/future verb forms

So in this sentence, you know the speaker is female because of מתבלבלת.

It is the present tense, feminine singular form of להתבלבל.

Dictionary form:

• להתבלבל = to get confused, to mix things up

This specific form:

• מתבלבלת = getting confused / confused / mixing things up

Hebrew present tense often works like a participle, so it can cover meanings that English expresses with am confused, get confused, or am getting confused, depending on context.

Because in Hebrew, present-tense sentences usually do not use a separate word for am / is / are.

So instead of saying something literally like I am confused, Hebrew often just uses the present-tense form:

• אני מתבלבלת = I get confused / I’m confused / I mix things up

That is normal Hebrew grammar.

This is a very common question.

• מתבלבלת comes from להתבלבל = to get confused / to mix things up oneself
• מבלבלת comes from לבלבל = to confuse / to mix up something or someone

So:

• אני מתבלבלת בין שתי הכתובות האלה
  = I get confused between / I mix up these two addresses
• הכתובות האלה מבלבלות אותי
  = These addresses confuse me

In this sentence, the speaker is the one experiencing the confusion, so מתבלבלת is the right choice.

בין means between (and sometimes among, depending on context).

Here it introduces the things the speaker is confusing:

• בין שתי הכתובות האלה = between these two addresses

Hebrew often uses בין with two items, for example:

• בין הבית לבית הספר = between the house and the school

But here the two items are packaged into one phrase, שתי הכתובות האלה = these two addresses, so you do not need to list them separately.

Because כתובות is a feminine plural noun, and the number two changes form before nouns.

Before nouns, Hebrew uses the construct forms:

• שני
  • masculine noun
• שתי
  • feminine noun

Since כתובת is feminine, you get:

• שתי כתובות = two addresses

By contrast, שתיים is the standalone form, used when no noun follows:

• יש לי שתיים = I have two

So in this sentence, שתי is exactly what you want.

Its singular form is כתובת, which is a feminine noun.

So:

• singular: כתובת
• plural: כתובות

Because the noun is feminine, other words connected to it follow feminine agreement where relevant, such as שתי.

Because the phrase is definite: these two addresses.

In Hebrew, when a noun phrase with a number is definite, the definite article usually goes on the noun:

• שתי כתובות = two addresses
• שתי הכתובות האלה = these two addresses

So הכתובות means the addresses, and then האלה adds these.

Because that is the normal Hebrew pattern for demonstratives like this / these.

Hebrew usually says:

• הכתובות האלה = these addresses
• literally something like the-addresses these

That is different from English, where these comes before the noun.

Some more examples:

• הספר הזה = this book
• הילדה הזאת = this girl
• הבתים האלה = these houses

Yes. In Modern Hebrew, both האלה and האלו are common after a definite noun.

So both of these work:

• הכתובות האלה
• הכתובות האלו

Both mean these addresses.
האלה is extremely common, and האלו is also very natural.

Because אני תמיד מתבלבלת... is a very natural neutral word order in Hebrew.

• אני תמיד מתבלבלת = I always get confused

You could also say:

• תמיד אני מתבלבלת...

That version is also possible, but it can sound a little more emphatic, like I’m always the one who gets confused... or I always...

So the original sentence is just a normal, straightforward way to say it.

Yes. Only the present-tense verb would change:

• אני תמיד מתבלבל בין שתי הכתובות האלה.

Everything else stays the same.

So the contrast is:

• female speaker: מתבלבלת
• male speaker: מתבלבל

It can mean several kinds of address, depending on context.

כתובת / כתובות can refer to:

• a street/postal address
• an email address
• a web address

So context tells you which kind of address is meant. In this sentence, if no other context is given, many learners would first think of physical addresses, but other meanings are possible too.