Studying as an employee

3 Yyears ago i, I was starting my career as a software engineer.

It was just graduate at this time that I graduated and the company where i madeI did my internship hired me.

Sounds more natural to reorder it. You could also use "Just at the time when I graduated, ..."

At this time i was already owner of the bhad a Bachelor's degree in the fields of economyics.

After my first year as an employee in athe company, iI wanted to get a mMaster's degree in the economy fieldics.

1. Note: You often says " 's degree", like "Bachelor's degree", "Master's Degree", etc.

2. It's unnecessary to say "field of [economics]". Usually the phrase "field of X" is only used once, and then the name is simply used over and over.

But as an employee it is really difficult to get back into the university.

Because you have to work atfrom 9 to 6.

B, because iI just started to be financially independaent.

Linking this to the previous sentence would be better in writing.

And if iI stopped working and continued studying iI cannoouldn't sustain myself.

1. "wouldn't be able to sustain" might also be used (instead of "couldn't sustain")

2. When talking about a hypothetical/imaginary situation using words like "if ...", you use the subjunctive (I see you speak French natively, you have it too, I believe?). However mostly in nowadays' English, most people just use the past tense, except for "If ... were to ...", which is sometimes but not always used.) (e.g: "If I were to stop, I'd lose.")

So iI put this project on standby and continued working.

And now iI just fiound out about these online mMasterclass program where you can learn at your own rythmpace.

1."Masterclass" is a pretty recent but common term for these kind of classes.

2. "at your own pace" sounds more natural here.

Studying as an employee

3 Yyears ago iI was starting my career as a software engineer.

"I" should always be capitalised when it's on its own as a word.
"3" is the start of the sentance, so "y" doesn't need to be capitalised. It's the same as if the number was written out, i.e. "Three years ago..."

I had just graduated at this time and the company where i madeI did my internship hired me.

Or "the company I interned at hired me."

At this time i wasI already owner of thehave a bachelor degree in the fields of economyics.

Or "At that time I already had a bachelor's degree in the field of economics."

Economics is only one field, so it's not plural.

You could also write "a bachelor's degree in economics."

After my first year as an employee in a company, iI wanted to get a master's degree in the economy fieldics.

Or "a master's in economics."

But as an employee it is really difficult to get back to the university because you have to work from 9 to 6.

I think it's nicer to have these two sentences connected.

Because you have to work atfrom 9 to 6.

Because iI just started to be financially independant, and if I stop working and continue studying I will not be able to sustain myself.

And if iI stop working and continue studying i cannotI will not be able to sustain myself.

So iI will put this project on standby and continue working.

Or "So I put this project on standby and continued working."

"Project" isn't quite right here. Maybe "goal" is better?

And now i just find I recently found out about these online master program where you can learn at your own rythm.