One day, my friend gave me a gift,: an expensive pencil.

At thate time, I didn't mind to usecare about any kind of pens.

You refer to pencil before and to pen here. If you mean that you didn't have a mind for pencils and pens, it may be best to say "At the time, I didn't care about any kind of writing instrument."

After using the pencil when writing a note, I was shocked its quality when writing down on my note.

As a result, I gotbecame curious about writing instruments, and. I have tried to use as many as possible.

These days, I use seven fountain pens that each hasve different colors these days.

I bought four of them during traveling in Japan, Poland and Canada, so. I can reminisce myabout the good old days when I use them.

Three pens are mywere birthday gifts and I gotreceived them with their own colors such as amethyst, fluorescent green, and blue-green.

I willTo have an excuse to use the pens, I try to write as much as possible to use the pens.

One day, my friend gave me a gift,ifted me an expensive pencil.

At that time, I didn't mind to useusing any kind of pens.

After using the pencil, I was shocked by its quality when writing down on my notes.

As a result, I got curious about writing instruments, and I have tried to use as many as possible.

These days, I use seven fountain pens that each hasve a different colors these days.

I bought four of them duringwhile traveling to Japan, Poland and Canada, so that I can reminisce on my good old days when I use them.

Three pens awere my birthday gifts and I got them with their own colors such as; amethyst, fluorescent green and blue-green.

With these pens, I can feel different touchsensations while writing on the paper.

I will try to write as much as possible toso I can use the pens.

One day, my friend gave me a gift, - an expensive fountain pencil.

By "pencil," do you mean 연필 or 만년필?
Because the title of this journal is "My Fountain Pen," I expected the first sentence to say that your friend gave you a fountain pen as a gift, not a pencil. I was a little confused.

At that time, I didn't mind to use anyhave a preference for a specific kind of pens.

You could also say "I didn't mind using" here. That sounds more natural than "I didn't mind to use."

After using the fountain pencil, I was shocked by its quality when writing down oin my notebook.

As a result, I got curious about other kinds of writing instruments, and I have tried to use as many as possible.

I usThese days, I have seven fountain pens that- and each has a different colors these days.

I bought four of them duringwhile traveling in Japan, Poland and Canada, so I can reminisceember my good old dayexperiences when I use them.

TI received three pens are mys birthday gifts, and I got them with their owin colors such aslike amethyst, fluorescent green and blue-green.

Changed some words to sound more natural.

With these pens, I can feel different touchextures while writing on the paper.

I think the word you want to use here is "textures," but if I am wrong, please describe it more in the comments and I can try to help!

I will try to write as much as possible to useusing the pens.

At that time, I didn't mind to useusing any kind of pens.

You could also say "At that time, I didn't mind what kind of pen I used"

After using the pencil, I was shocked by its quality when writing down on my notes.

As a result, I got/became curious about writing instruments, and I have tried to use as many (different ones) as possible.

I use seven fountain pens that each hasve different colors (these days).

I bought four of them duringwhen travelling to Japan, Poland and Canada, so I can reminisce about my good old days when I use them.

Threee three other pens are my birthday gifts and I got them with their own colors such as amethyst, fluorescent green and blue-green.

With these pens, I can feel different touches while writing on the paper.

I will try to write as much as possible to/and use the pens.

At that time, I didn't mind to useing any kind of pens.

After using the pencil, I was shocked by its quality when writing down on my notes.

I use seven fountain pens that each hasve different colors these days.

I bought four of them duringwhile traveling to Japan, Poland and Canada, so I can reminisce myabout the good old days when I use them.

Three pens awere my birthday gifts and I got them with their own colors such as amethyst, fluorescent green and blue-green.

With these pens, I can feel different touchs while writing on the paper.

what you mean by "touchs"?

I will try to write as much as possible to useusing the pens.