Would "pendant ma jeunesse" be just as acceptable? If not, what's the subtle difference?
The subtle difference: - J'ai été malade "durant" mon voyage = pendant TOUT le voyage ----------- - J'ai été malade "pendant" le voyage = pendant la totalité OU une partie du voyage. ------- (source: http://www.francaisfacile.com/forum/lire.php?num=7&msg=38005&titre=Pendant+%2F+durant)
I recommend opening another tab on your browser for a good French-English dictionary: http://www.larousse.com/en/dictionaries/english-french/childhood/569796
what's the difference between 'pendant' and 'durant?' Is 'pendant' more like 'while,' whereas durant is more like, 'during'? Or are they synonymous?
Pendant and durant are synonymous prepositions meaning during. Durant is less common and cannot turn into a conjunction. Pendant can become a conjunction with the addition of que. Pendant que = while.
I was very tempted to try "When I was young" but I think that would be just a little off the mark. Always go with the sure thing, the most simple and direct and proper (etc.). If you want to find out about other possibilities, check these discussions after you get it right.