My lLast hHoliday

Last Sunday, I and my girlfriends and I went to the exhibition of my favorite autheor at Kyobashi, Tokyo.

At first, we're so surprised because the venue was highly crowded by many guests.

It's not wrong to include it but just a little redundant

We' were required to wait 3 hours to entirer the venue!

It' was fantastic!

Last Sunday, I and my girlfriends and I went to the exhibition of my favorite autheor at Kyobashi, Tokyo.

Just a little bit of misspelling along with some placement issues.

At first, we' were so surprised because the venue was highlvery crowded by many guests.

All I did was simplify the sentence a little and changed the word, “we’re” ‘s tense.

We're require had to wait 3 hours to entirer the venue!

I think you mean, “enter”, not “entire”.

So, we got a reservation and went to a cafe.

This is mainly a preference thing, but, to me, it only looks right this way.

Thise cafe provided us great cheese cakegave us cheese cakes that tasted delicious!

This is a more proper way of saying this phrase.

We may visitSince we really liked it, we might go back to thise cafe again.

My version is just more detailed, but your version also works.

Last Sunday, I and my girlfriends and I went to the exhibition of my favorite autheor at Kyobashi, Tokyo.

To add on to what others have said, while "I and my girlfriends" is not technically incorrect, it is far more common to say "my girlfriends and I". I believe it's a matter of courtesy—it's considered more polite to put "I" at the end, and over time this evolved to be the standard.

This cafe provided us great cheese cakes!

This is a little nitpicky...but "cheesecakes" is one word. Not a big deal though! :P

Last Sunday, Ime and my girlfriends went to the exhibition of my favorite autheor at Kyobashi, Tokyo.

At first, we' were so surprised because the venue was highly crowded by, with many guests.

We're require had to wait 3 hours to entirer the venue!

My lLast hHoliday

Last Sunday, I and my girlfriends and I went to thean exhibition of my favorite autheor atin Kyobashi, Tokyo.

The comma included in the beginning isn't necessary because there's no need to pause after reading "Last Sunday". Other than the minor grammar mistakes this was written well.

At first,We we're so surprised at first because the venue was highlvery crowded by many guests.

'we're' wouldn't make sense in the sentence because 'we're' is present tense.
Since you are speaking in the past tense with 'surprised' and 'crowded', you would use 'we were' instead (or similar).
Using two words to describe the amount of people in the venue can make your sentence sound unnatural.
Since you described the venue as crowded with lots of guests, 'very' can be an easy way to describe how busy it was without crowding your sentence.

Nice work

We' were required to wait 3 hours to entirer the venue!

'we're' is present tense

only a single grammar error but the sentence is understandable with context.

Thise cafe provided us great cheese cakes!

For this sentence i think 'the' would be a better word to use because you have the context that you are already going to a cafe, so it will be that one. "This cafe" is still good but 'the' flows better with the rest of your sentences.

It' was fantastic!

'It's' is present tense, Using 'It was' will make it past tense, which is better for this story since you are writing mostly in past tense.