I had a subscribedption to a science manazine when I was a high school student. I had a subscription to a science manazine when I was a high school student.

You could also write here "I was subscribed to".

There was no enough space to store it in my room, so I cancelled the subscription when I was in college. There was no enough space to store it in my room, so I cancelled the subscription when I was in college.

With my son's help, I fiound out that the magazine is now published ias an e-book. With my son's help, I found out that the magazine is now published as an e-book.

When saying that something is being published in some form/format, you say "as a(n) ..." usually.

I buyought it right after thatwards, and now I am reading it. I bought it right afterwards, and now I am reading it.

"after that" isn't wrong, it just sounds a bit off, this is more natural when talking about events that happened a while ago.

It is still just as interesteding for me. It is still just as interesting for me.

I added "just as" because I think you wre trying to say you still found it as interesting as you did before.