Good (upbringing?) since childhood

I never thought about our hobbies or education like a good investments for the future. But once my mind was changed by a meeting. (But I once had my mind changed by a meeting.)
When your parents tell you (and you are a little boy or girl with a wind inside your head.) about the use of good classes, it sounds like "bla-bla-bla....", and you continue to do what you did before. 

But once I was introduced to a fellow. We started to talk and I noticed, that he caught little intonations in the conversation and understood, what you didn't voice. I found out, that he was a winner in some musical competitions.
After that new acquaintances of mine (who was connected with music.) also born out my notice. (This sentence makes little sense to me; it seems incomplete.)
And now I think, that all lessons that we learned in the childhood, or abilities we have now developed, or will develop from now; such as the music developed in meetings of mine that give a good feeling.

Very good.
In there first sentence you had a mixed singular and plural clause (like a good investments). "Investments" is plural, therefore "a investments" is not grammatically correct.

The second part of the sentence makes sense, but sounds clumsy.

Unlike in Russian, in English we capitalise "I" in sentences, even if it is not first in the sentence.

The last sentence I found difficult to understand. Perhaps someone who has a good grasp in both English and Russian can help you with that part.