There's no usual memory

How\'s your morning [이름]?

I hope everything is going well there. Anyway, kindly check out the corrections below.

See you.

~Teacher Shanee^^,

As soon as I was discharged from the military service(About.. 22years old), I went to the beach with my high school friends.

>>> Correct! (OR: As soon as I was discharged from the military, that was when I was about 22 years old, I went to the beach with my high school friends.)

Before I had experience that, I thought two nights and three days are too long and expensive to pay for me.

>>> Before I had experienced that, I thought two night and three days of a getaway is too long and expensive for me.

But once I was headed to beach and passed just one day, My thought was changed.

>>> But when I was once passing by the beach, I changed my mind.

Rather, two nights were too short to enjoy enough. 

>>> Rather, two nights was too short to enjoy.

Actually, There was nothing special.

>>> Actually, there was nothing special.

It’s just a normal story whoever can experience.

>>> Correct!

Perhaps, I think many people experience already.

>>> Perhaps, many people experienced that already.

I dove into the sea, ate some delicious things, talked with my friends all nights.

>>> I dove into the sea, ate some delicious food and talked with my friends all night.

That’s all.

>>> Correct!

I know this is not special at all.

>>> Correct!

But you know why do I pick up this story as the best memory I had ever?

>>> But do you know why I chose this story as the best memory I ever had?

That’s not an issue what I did. The point is Who was with me.
>>> It\'s because of I was with.

And The reason the memory remains me in the long time is I know I can’t have a time to hang out again like that.

>>> And the reason the memory remains in me for a long time is I didn\'t have the chance to hung out again like that and I am not sure if I will ever have to.