השיטה הזאת טובה, אבל הקצב של השיעור היום היה מהיר מדי בשבילי.

Because שיטה (method) is a feminine noun in Hebrew.

The demonstrative this has to agree with the noun:

• masculine: הזה
• feminine: הזאת

So:

• הספר הזה = this book
• השיטה הזאת = this method

Notice also that in Hebrew, this/that usually comes after the noun, unlike in English.

For the same reason: שיטה is feminine, so the adjective must agree with it.

• masculine singular: טוב
• feminine singular: טובה

So:

• ספר טוב = a good book
• שיטה טובה = a good method

In the sentence, טובה describes השיטה.

That is the normal Hebrew word order for a noun with this/that:

• הספר הזה = this book
• האישה הזאת = this woman
• השיטה הזאת = this method

So Hebrew usually does:

noun + הזה / הזאת / האלה

not this + noun as in English.

היה is the past tense of to be for masculine singular.

In present-tense Hebrew, you usually do not say is:

• השיטה הזאת טובה = This method is good

But in the past, Hebrew does use was/were:

• הקצב ... היה מהיר = The pace ... was fast

So היה is necessary because the sentence is talking about the lesson’s pace in the past.

Because היה agrees with הקצב (the pace), and קצב is masculine singular.

• masculine singular: היה
• feminine singular: הייתה

So:

• הקצב היה מהיר = the pace was fast
• but: השיטה הייתה טובה = the method was good

Even though שיעור also appears nearby, the verb is agreeing with קצב, not with שיעור.

של means of or sometimes ’s.

So:

• הקצב של השיעור = the pace of the lesson / the lesson’s pace

This is a very common way to show possession or connection in modern Hebrew.

You may also hear a more compact form, especially in formal language:

• קצב השיעור

But הקצב של השיעור is very natural and clear.

Because היום here means today and modifies השיעור:
the lesson today / today’s lesson

Hebrew often places time words like היום after the noun:

• הפגישה היום = the meeting today
• השיעור היום = the lesson today

So:

• הקצב של השיעור היום = the pace of the lesson today

A learner might expect something more like today’s lesson, but Hebrew commonly uses this structure.

Yes, that is possible, and it can sound a little more explicit:

• הקצב של השיעור היום
• הקצב של השיעור של היום

Both can mean the pace of today’s lesson.

The version in your sentence is a bit leaner and very natural in conversation.

מדי means too in the sense of excessively.

So:

• מהיר מדי = too fast
• יקר מדי = too expensive
• קשה מדי = too difficult

In Hebrew, מדי normally comes after the adjective:

• fast too literally, but naturally too fast

So:

• היה מהיר מדי = was too fast

בשבילי literally means for me, and here it has the sense of:

• for me
• for my needs
• for my level
• from my perspective

So:

• מהיר מדי בשבילי = too fast for me

If you said מהיר לי, it would sound less natural here. Hebrew usually prefers בשבילי in this kind of sentence when talking about suitability.

Compare:

• זה קשה לי = this is hard for me
• זה מהיר מדי בשבילי = this is too fast for me

The prefix ה־ means the.

In this sentence, the speaker is referring to specific things:

• השיטה = the method
• הקצב = the pace
• השיעור = the lesson

Hebrew often uses definiteness where English also would, especially when talking about a particular method, a particular lesson, and that lesson’s pace.

Also remember that with this, the noun is usually definite:

• השיטה הזאת not usually שיטה הזאת

Yes. מהיר means fast/quick, and it works naturally here.

• קצב מהיר = a fast pace
• קצב איטי = a slow pace

So הקצב ... היה מהיר מדי is a very normal way to say the pace was too fast.

Yes:

• השיטה הזאת = this method
• טובה = is good
• אבל = but
• הקצב = the pace
• של השיעור היום = of today’s lesson
• היה = was
• מהיר מדי = too fast
• בשבילי = for me

So the structure is:

This method is good, but the pace of today’s lesson was too fast for me.

A natural pronunciation would be approximately:

ha-shi-TA ha-ZOT to-VA, a-VAL ha-KE-tsev shel ha-shi-UR ha-YOM ha-YA ma-HIR mi-DEI bish-vi-LI

A few helpful notes:

• השיטה stress on the last syllable: shi-TA
• הזאת stress on the last syllable: ha-ZOT
• השיעור stress on the last syllable: shi-UR
• מדי stress on the second syllable: mi-DEI
• בשבילי stress on the last syllable: bish-vi-LI

Yes, that is also a natural sentence.

That version means more literally: This method is good, but today’s lesson was too fast for me.

The original sentence is slightly more precise because it focuses specifically on the pace:

• אבל הקצב של השיעור היום היה מהיר מדי בשבילי
• but the pace of today’s lesson was too fast for me

So the original is a bit more exact, while your alternative is simpler and still very natural.