In primary school, I first learned to write with a pencil and then with a fountainpen, as you describe (I grew up in Europe). This has made no difference to my experience with writing whatsoever, because our <insert strong swear word> language/cursive/alphabet is designed for right-handed people. I could talk for hours on the subject, but it would involve much swearing — I will spare you the pain. Just know that we should be writing top-to-bottom instead of left to write, and should re-design our alphabet, cursive, fountain pen nibs, and how we teach lefties to write.
A note in left-handedness:
In primary school, I first learned to write with a pencil and then with a fountainpen, as you describe (I grew up in Europe). This has made no difference to my experience with writing whatsoever, because our <insert strong swear word> language/cursive/alphabet is designed for right-handed people. I could talk for hours on the subject, but it would involve much swearing — I will spare you the pain. Just know that we should be writing top-to-bottom instead of left to write, and should re-design our alphabet, cursive, fountain pen nibs, and how we teach lefties to write.